diff --git a/asn1_decoder.cpp b/asn1_decoder.cpp
index a9dfccc..285214f 100644
--- a/asn1_decoder.cpp
+++ b/asn1_decoder.cpp
@@ -19,14 +19,14 @@
 #include <stdint.h>
 
 int asn1_context::peek_byte() const {
-  if (length_ <= 0) {
+  if (length_ == 0) {
     return -1;
   }
   return *p_;
 }
 
 int asn1_context::get_byte() {
-  if (length_ <= 0) {
+  if (length_ == 0) {
     return -1;
   }
 
diff --git a/bootloader_message/bootloader_message.cpp b/bootloader_message/bootloader_message.cpp
index d8086be..d17e055 100644
--- a/bootloader_message/bootloader_message.cpp
+++ b/bootloader_message/bootloader_message.cpp
@@ -19,6 +19,7 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <string.h>
+#include <unistd.h>
 
 #include <string>
 #include <vector>
@@ -30,8 +31,13 @@
 #include <fs_mgr.h>
 
 static std::string get_misc_blk_device(std::string* err) {
-  std::unique_ptr<fstab, decltype(&fs_mgr_free_fstab)> fstab(fs_mgr_read_fstab_default(),
-                                                             fs_mgr_free_fstab);
+  std::unique_ptr<fstab, decltype(&fs_mgr_free_fstab)> fstab(nullptr, fs_mgr_free_fstab);
+  // Use different fstab paths for normal boot and recovery boot, respectively
+  if (access("/sbin/recovery", F_OK) == 0) {
+    fstab.reset(fs_mgr_read_fstab_with_dt("/etc/recovery.fstab"));
+  } else {
+    fstab.reset(fs_mgr_read_fstab_default());
+  }
   if (!fstab) {
     *err = "failed to read default fstab";
     return "";
diff --git a/edify/expr.cpp b/edify/expr.cpp
index 2b7fd7a..54ab332 100644
--- a/edify/expr.cpp
+++ b/edify/expr.cpp
@@ -357,7 +357,7 @@
     if (args == nullptr) {
         return false;
     }
-    if (len == 0 || start + len > argv.size()) {
+    if (start + len > argv.size()) {
         return false;
     }
     for (size_t i = start; i < start + len; ++i) {
diff --git a/otafault/ota_io.cpp b/otafault/ota_io.cpp
index f5b0113..3a89bb5 100644
--- a/otafault/ota_io.cpp
+++ b/otafault/ota_io.cpp
@@ -89,7 +89,7 @@
     return fclose(fh);
 }
 
-void OtaFcloser::operator()(FILE* f) {
+void OtaFcloser::operator()(FILE* f) const {
     __ota_fclose(f);
 };
 
diff --git a/otafault/ota_io.h b/otafault/ota_io.h
index 395b423..9428f1b 100644
--- a/otafault/ota_io.h
+++ b/otafault/ota_io.h
@@ -59,7 +59,7 @@
 int ota_close(unique_fd& fd);
 
 struct OtaFcloser {
-  void operator()(FILE*);
+  void operator()(FILE*) const;
 };
 
 using unique_file = std::unique_ptr<FILE, OtaFcloser>;
diff --git a/recovery.cpp b/recovery.cpp
index 91c511a..c226216 100644
--- a/recovery.cpp
+++ b/recovery.cpp
@@ -53,6 +53,7 @@
 #include <cutils/properties.h> /* for property_list */
 #include <healthd/BatteryMonitor.h>
 #include <private/android_logger.h> /* private pmsg functions */
+#include <private/android_filesystem_config.h>  /* for AID_SYSTEM */
 #include <selinux/label.h>
 #include <selinux/selinux.h>
 #include <ziparchive/zip_archive.h>
@@ -460,9 +461,9 @@
     copy_log_file(TEMPORARY_INSTALL_FILE, LAST_INSTALL_FILE, false);
     save_kernel_log(LAST_KMSG_FILE);
     chmod(LOG_FILE, 0600);
-    chown(LOG_FILE, 1000, 1000);   // system user
+    chown(LOG_FILE, AID_SYSTEM, AID_SYSTEM);
     chmod(LAST_KMSG_FILE, 0600);
-    chown(LAST_KMSG_FILE, 1000, 1000);   // system user
+    chown(LAST_KMSG_FILE, AID_SYSTEM, AID_SYSTEM);
     chmod(LAST_LOG_FILE, 0640);
     chmod(LAST_INSTALL_FILE, 0644);
     sync();
@@ -751,13 +752,15 @@
 
 static bool prompt_and_wipe_data(Device* device) {
   const char* const headers[] = {
-    "Boot halted, user data is corrupt",
-    "Wipe all user data to recover",
+    "Can't load Android system. Your data may be corrupt.",
+    "If you continue to get this message, you may need to",
+    "perform a factory data reset and erase all user data",
+    "stored on this device.",
     NULL
   };
   const char* const items[] = {
-    "Retry boot",
-    "Wipe user data",
+    "Try again",
+    "Factory data reset",
     NULL
   };
   for (;;) {
@@ -790,47 +793,45 @@
     return success;
 }
 
-// Secure-wipe a given partition. It uses BLKSECDISCARD, if supported.
-// Otherwise, it goes with BLKDISCARD (if device supports BLKDISCARDZEROES) or
-// BLKZEROOUT.
+// Secure-wipe a given partition. It uses BLKSECDISCARD, if supported. Otherwise, it goes with
+// BLKDISCARD (if device supports BLKDISCARDZEROES) or BLKZEROOUT.
 static bool secure_wipe_partition(const std::string& partition) {
-    android::base::unique_fd fd(TEMP_FAILURE_RETRY(open(partition.c_str(), O_WRONLY)));
-    if (fd == -1) {
-        PLOG(ERROR) << "failed to open \"" << partition << "\"";
+  android::base::unique_fd fd(TEMP_FAILURE_RETRY(open(partition.c_str(), O_WRONLY)));
+  if (fd == -1) {
+    PLOG(ERROR) << "Failed to open \"" << partition << "\"";
+    return false;
+  }
+
+  uint64_t range[2] = { 0, 0 };
+  if (ioctl(fd, BLKGETSIZE64, &range[1]) == -1 || range[1] == 0) {
+    PLOG(ERROR) << "Failed to get partition size";
+    return false;
+  }
+  LOG(INFO) << "Secure-wiping \"" << partition << "\" from " << range[0] << " to " << range[1];
+
+  LOG(INFO) << "  Trying BLKSECDISCARD...";
+  if (ioctl(fd, BLKSECDISCARD, &range) == -1) {
+    PLOG(WARNING) << "  Failed";
+
+    // Use BLKDISCARD if it zeroes out blocks, otherwise use BLKZEROOUT.
+    unsigned int zeroes;
+    if (ioctl(fd, BLKDISCARDZEROES, &zeroes) == 0 && zeroes != 0) {
+      LOG(INFO) << "  Trying BLKDISCARD...";
+      if (ioctl(fd, BLKDISCARD, &range) == -1) {
+        PLOG(ERROR) << "  Failed";
         return false;
-    }
-
-    uint64_t range[2] = {0, 0};
-    if (ioctl(fd, BLKGETSIZE64, &range[1]) == -1 || range[1] == 0) {
-        PLOG(ERROR) << "failed to get partition size";
+      }
+    } else {
+      LOG(INFO) << "  Trying BLKZEROOUT...";
+      if (ioctl(fd, BLKZEROOUT, &range) == -1) {
+        PLOG(ERROR) << "  Failed";
         return false;
+      }
     }
-    printf("Secure-wiping \"%s\" from %" PRIu64 " to %" PRIu64 ".\n",
-           partition.c_str(), range[0], range[1]);
+  }
 
-    printf("Trying BLKSECDISCARD...\t");
-    if (ioctl(fd, BLKSECDISCARD, &range) == -1) {
-        printf("failed: %s\n", strerror(errno));
-
-        // Use BLKDISCARD if it zeroes out blocks, otherwise use BLKZEROOUT.
-        unsigned int zeroes;
-        if (ioctl(fd, BLKDISCARDZEROES, &zeroes) == 0 && zeroes != 0) {
-            printf("Trying BLKDISCARD...\t");
-            if (ioctl(fd, BLKDISCARD, &range) == -1) {
-                printf("failed: %s\n", strerror(errno));
-                return false;
-            }
-        } else {
-            printf("Trying BLKZEROOUT...\t");
-            if (ioctl(fd, BLKZEROOUT, &range) == -1) {
-                printf("failed: %s\n", strerror(errno));
-                return false;
-            }
-        }
-    }
-
-    printf("done\n");
-    return true;
+  LOG(INFO) << "  Done";
+  return true;
 }
 
 // Check if the wipe package matches expectation:
@@ -862,7 +863,7 @@
         return false;
     }
     std::string metadata;
-    if (!read_metadata_from_package(&zip, &metadata)) {
+    if (!read_metadata_from_package(zip, &metadata)) {
         CloseArchive(zip);
         return false;
     }
diff --git a/screen_ui.cpp b/screen_ui.cpp
index 706877b..bb2772d 100644
--- a/screen_ui.cpp
+++ b/screen_ui.cpp
@@ -98,7 +98,7 @@
     }
 }
 
-int ScreenRecoveryUI::PixelsFromDp(int dp) {
+int ScreenRecoveryUI::PixelsFromDp(int dp) const {
     return dp * density_;
 }
 
@@ -256,12 +256,12 @@
     *y += 4;
 }
 
-void ScreenRecoveryUI::DrawTextLine(int x, int* y, const char* line, bool bold) {
+void ScreenRecoveryUI::DrawTextLine(int x, int* y, const char* line, bool bold) const {
     gr_text(gr_sys_font(), x, *y, line, bold);
     *y += char_height_ + 4;
 }
 
-void ScreenRecoveryUI::DrawTextLines(int x, int* y, const char* const* lines) {
+void ScreenRecoveryUI::DrawTextLines(int x, int* y, const char* const* lines) const {
     for (size_t i = 0; lines != nullptr && lines[i] != nullptr; ++i) {
         DrawTextLine(x, y, lines[i], false);
     }
diff --git a/screen_ui.h b/screen_ui.h
index b2dcf4a..a2322c3 100644
--- a/screen_ui.h
+++ b/screen_ui.h
@@ -160,14 +160,14 @@
     void LoadBitmap(const char* filename, GRSurface** surface);
     void LoadLocalizedBitmap(const char* filename, GRSurface** surface);
 
-    int PixelsFromDp(int dp);
+    int PixelsFromDp(int dp) const;
     virtual int GetAnimationBaseline();
     virtual int GetProgressBaseline();
     virtual int GetTextBaseline();
 
     void DrawHorizontalRule(int* y);
-    void DrawTextLine(int x, int* y, const char* line, bool bold);
-    void DrawTextLines(int x, int* y, const char* const* lines);
+    void DrawTextLine(int x, int* y, const char* line, bool bold) const;
+    void DrawTextLines(int x, int* y, const char* const* lines) const;
 };
 
 #endif  // RECOVERY_UI_H
diff --git a/ui.cpp b/ui.cpp
index a796461..9194ae3 100644
--- a/ui.cpp
+++ b/ui.cpp
@@ -240,7 +240,7 @@
 }
 
 void* RecoveryUI::time_key_helper(void* cookie) {
-    key_timer_t* info = (key_timer_t*) cookie;
+    key_timer_t* info = static_cast<key_timer_t*>(cookie);
     info->ui->time_key(info->key_code, info->count);
     delete info;
     return nullptr;
diff --git a/updater/blockimg.cpp b/updater/blockimg.cpp
index efdfec1..c614ccc 100644
--- a/updater/blockimg.cpp
+++ b/updater/blockimg.cpp
@@ -356,7 +356,7 @@
 }
 
 static void* unzip_new_data(void* cookie) {
-    NewThreadInfo* nti = (NewThreadInfo*) cookie;
+    NewThreadInfo* nti = static_cast<NewThreadInfo*>(cookie);
     ProcessZipEntryContents(nti->za, &nti->entry, receive_new_data, nti);
     return nullptr;
 }
@@ -429,46 +429,11 @@
     uint8_t* patch_start;
 };
 
-// Do a source/target load for move/bsdiff/imgdiff in version 1.
-// We expect to parse the remainder of the parameter tokens as:
-//
-//    <src_range> <tgt_range>
-//
-// The source range is loaded into the provided buffer, reallocating
-// it to make it larger if necessary.
-
-static int LoadSrcTgtVersion1(CommandParameters& params, RangeSet& tgt, size_t& src_blocks,
-        std::vector<uint8_t>& buffer, int fd) {
-
-    if (params.cpos + 1 >= params.tokens.size()) {
-        LOG(ERROR) << "invalid parameters";
-        return -1;
-    }
-
-    // <src_range>
-    RangeSet src = parse_range(params.tokens[params.cpos++]);
-
-    // <tgt_range>
-    tgt = parse_range(params.tokens[params.cpos++]);
-
-    allocate(src.size * BLOCKSIZE, buffer);
-    int rc = ReadBlocks(src, buffer, fd);
-    src_blocks = src.size;
-
-    return rc;
-}
-
 // Print the hash in hex for corrupted source blocks (excluding the stashed blocks which is
 // handled separately).
 static void PrintHashForCorruptedSourceBlocks(const CommandParameters& params,
                                               const std::vector<uint8_t>& buffer) {
   LOG(INFO) << "unexpected contents of source blocks in cmd:\n" << params.cmdline;
-  if (params.version < 3) {
-    // TODO handle version 1,2
-    LOG(WARNING) << "version number " << params.version << " is not supported to print hashes";
-    return;
-  }
-
   CHECK(params.tokens[0] == "move" || params.tokens[0] == "bsdiff" ||
         params.tokens[0] == "imgdiff");
 
@@ -651,8 +616,8 @@
   }
 }
 
-static int LoadStash(CommandParameters& params, const std::string& base, const std::string& id,
-        bool verify, size_t* blocks, std::vector<uint8_t>& buffer, bool printnoent) {
+static int LoadStash(CommandParameters& params, const std::string& id, bool verify, size_t* blocks,
+                     std::vector<uint8_t>& buffer, bool printnoent) {
     // In verify mode, if source range_set was saved for the given hash,
     // check contents in the source blocks first. If the check fails,
     // search for the stashed files on /cache as usual.
@@ -674,17 +639,13 @@
         }
     }
 
-    if (base.empty()) {
-        return -1;
-    }
-
     size_t blockcount = 0;
 
     if (!blocks) {
         blocks = &blockcount;
     }
 
-    std::string fn = GetStashFileName(base, id, "");
+    std::string fn = GetStashFileName(params.stashbase, id, "");
 
     struct stat sb;
     int res = stat(fn.c_str(), &sb);
@@ -735,7 +696,7 @@
 }
 
 static int WriteStash(const std::string& base, const std::string& id, int blocks,
-        std::vector<uint8_t>& buffer, bool checkspace, bool *exists) {
+                      std::vector<uint8_t>& buffer, bool checkspace, bool *exists) {
     if (base.empty()) {
         return -1;
     }
@@ -895,52 +856,6 @@
   return 0;  // Using existing directory
 }
 
-static int SaveStash(CommandParameters& params, const std::string& base,
-        std::vector<uint8_t>& buffer, int fd, bool usehash) {
-
-    // <stash_id> <src_range>
-    if (params.cpos + 1 >= params.tokens.size()) {
-        LOG(ERROR) << "missing id and/or src range fields in stash command";
-        return -1;
-    }
-    const std::string& id = params.tokens[params.cpos++];
-
-    size_t blocks = 0;
-    if (usehash && LoadStash(params, base, id, true, &blocks, buffer, false) == 0) {
-        // Stash file already exists and has expected contents. Do not
-        // read from source again, as the source may have been already
-        // overwritten during a previous attempt.
-        return 0;
-    }
-
-    RangeSet src = parse_range(params.tokens[params.cpos++]);
-
-    allocate(src.size * BLOCKSIZE, buffer);
-    if (ReadBlocks(src, buffer, fd) == -1) {
-        return -1;
-    }
-    blocks = src.size;
-    stash_map[id] = src;
-
-    if (usehash && VerifyBlocks(id, buffer, blocks, true) != 0) {
-        // Source blocks have unexpected contents. If we actually need this
-        // data later, this is an unrecoverable error. However, the command
-        // that uses the data may have already completed previously, so the
-        // possible failure will occur during source block verification.
-        LOG(ERROR) << "failed to load source blocks for stash " << id;
-        return 0;
-    }
-
-    // In verify mode, we don't need to stash any blocks.
-    if (!params.canwrite && usehash) {
-        return 0;
-    }
-
-    LOG(INFO) << "stashing " << blocks << " blocks to " << id;
-    params.stashed += blocks;
-    return WriteStash(base, id, blocks, buffer, false, nullptr);
-}
-
 static int FreeStash(const std::string& base, const std::string& id) {
   if (base.empty() || id.empty()) {
     return -1;
@@ -980,13 +895,12 @@
 //    <tgt_range> <src_block_count> <src_range> <src_loc> <[stash_id:stash_range] ...>
 //        (loads data from both source image and stashes)
 //
-// On return, buffer is filled with the loaded source data (rearranged
-// and combined with stashed data as necessary).  buffer may be
-// reallocated if needed to accommodate the source data.  *tgt is the
-// target RangeSet.  Any stashes required are loaded using LoadStash.
+// On return, params.buffer is filled with the loaded source data (rearranged and combined with
+// stashed data as necessary). buffer may be reallocated if needed to accommodate the source data.
+// *tgt is the target RangeSet. Any stashes required are loaded using LoadStash.
 
 static int LoadSrcTgtVersion2(CommandParameters& params, RangeSet& tgt, size_t& src_blocks,
-        std::vector<uint8_t>& buffer, int fd, const std::string& stashbase, bool* overlap) {
+                              bool* overlap) {
 
     // At least it needs to provide three parameters: <tgt_range>,
     // <src_block_count> and "-"/<src_range>.
@@ -1005,7 +919,7 @@
         return -1;
     }
 
-    allocate(src_blocks * BLOCKSIZE, buffer);
+    allocate(src_blocks * BLOCKSIZE, params.buffer);
 
     // "-" or <src_range> [<src_loc>]
     if (params.tokens[params.cpos] == "-") {
@@ -1013,7 +927,7 @@
         params.cpos++;
     } else {
         RangeSet src = parse_range(params.tokens[params.cpos++]);
-        int res = ReadBlocks(src, buffer, fd);
+        int res = ReadBlocks(src, params.buffer, params.fd);
 
         if (overlap) {
             *overlap = range_overlaps(src, tgt);
@@ -1029,7 +943,7 @@
         }
 
         RangeSet locs = parse_range(params.tokens[params.cpos++]);
-        MoveRange(buffer, locs, buffer);
+        MoveRange(params.buffer, locs, params.buffer);
     }
 
     // <[stash_id:stash_range]>
@@ -1044,7 +958,7 @@
         }
 
         std::vector<uint8_t> stash;
-        int res = LoadStash(params, stashbase, tokens[0], false, nullptr, stash, true);
+        int res = LoadStash(params, tokens[0], false, nullptr, stash, true);
 
         if (res == -1) {
             // These source blocks will fail verification if used later, but we
@@ -1055,32 +969,41 @@
 
         RangeSet locs = parse_range(tokens[1]);
 
-        MoveRange(buffer, locs, stash);
+        MoveRange(params.buffer, locs, stash);
     }
 
     return 0;
 }
 
-// Do a source/target load for move/bsdiff/imgdiff in version 3.
-//
-// Parameters are the same as for LoadSrcTgtVersion2, except for 'onehash', which
-// tells the function whether to expect separate source and targe block hashes, or
-// if they are both the same and only one hash should be expected, and
-// 'isunresumable', which receives a non-zero value if block verification fails in
-// a way that the update cannot be resumed anymore.
-//
-// If the function is unable to load the necessary blocks or their contents don't
-// match the hashes, the return value is -1 and the command should be aborted.
-//
-// If the return value is 1, the command has already been completed according to
-// the contents of the target blocks, and should not be performed again.
-//
-// If the return value is 0, source blocks have expected content and the command
-// can be performed.
-
+/**
+ * Do a source/target load for move/bsdiff/imgdiff in version 3.
+ *
+ * We expect to parse the remainder of the parameter tokens as one of:
+ *
+ *    <tgt_range> <src_block_count> <src_range>
+ *        (loads data from source image only)
+ *
+ *    <tgt_range> <src_block_count> - <[stash_id:stash_range] ...>
+ *        (loads data from stashes only)
+ *
+ *    <tgt_range> <src_block_count> <src_range> <src_loc> <[stash_id:stash_range] ...>
+ *        (loads data from both source image and stashes)
+ *
+ * Parameters are the same as for LoadSrcTgtVersion2, except for 'onehash', which tells the function
+ * whether to expect separate source and targe block hashes, or if they are both the same and only
+ * one hash should be expected, and 'isunresumable', which receives a non-zero value if block
+ * verification fails in a way that the update cannot be resumed anymore.
+ *
+ * If the function is unable to load the necessary blocks or their contents don't match the hashes,
+ * the return value is -1 and the command should be aborted.
+ *
+ * If the return value is 1, the command has already been completed according to the contents of the
+ * target blocks, and should not be performed again.
+ *
+ * If the return value is 0, source blocks have expected content and the command can be performed.
+ */
 static int LoadSrcTgtVersion3(CommandParameters& params, RangeSet& tgt, size_t& src_blocks,
-        bool onehash, bool& overlap) {
-
+                              bool onehash, bool& overlap) {
     if (params.cpos >= params.tokens.size()) {
         LOG(ERROR) << "missing source hash";
         return -1;
@@ -1099,8 +1022,7 @@
         tgthash = params.tokens[params.cpos++];
     }
 
-    if (LoadSrcTgtVersion2(params, tgt, src_blocks, params.buffer, params.fd,
-                           params.stashbase, &overlap) == -1) {
+    if (LoadSrcTgtVersion2(params, tgt, src_blocks, &overlap) == -1) {
         return -1;
     }
 
@@ -1111,7 +1033,7 @@
     }
 
     if (VerifyBlocks(tgthash, tgtbuffer, tgt.size, false) == 0) {
-        // Target blocks already have expected content, command should be skipped
+        // Target blocks already have expected content, command should be skipped.
         return 1;
     }
 
@@ -1130,25 +1052,24 @@
             }
 
             params.stashed += src_blocks;
-            // Can be deleted when the write has completed
+            // Can be deleted when the write has completed.
             if (!stash_exists) {
                 params.freestash = srchash;
             }
         }
 
-        // Source blocks have expected content, command can proceed
+        // Source blocks have expected content, command can proceed.
         return 0;
     }
 
-    if (overlap && LoadStash(params, params.stashbase, srchash, true, nullptr, params.buffer,
-                             true) == 0) {
+    if (overlap && LoadStash(params, srchash, true, nullptr, params.buffer, true) == 0) {
         // Overlapping source blocks were previously stashed, command can proceed.
         // We are recovering from an interrupted command, so we don't know if the
         // stash can safely be deleted after this command.
         return 0;
     }
 
-    // Valid source data not available, update cannot be resumed
+    // Valid source data not available, update cannot be resumed.
     LOG(ERROR) << "partition has unexpected contents";
     PrintHashForCorruptedSourceBlocks(params, params.buffer);
 
@@ -1158,77 +1079,101 @@
 }
 
 static int PerformCommandMove(CommandParameters& params) {
-    size_t blocks = 0;
-    bool overlap = false;
-    int status = 0;
-    RangeSet tgt;
+  size_t blocks = 0;
+  bool overlap = false;
+  RangeSet tgt;
+  int status = LoadSrcTgtVersion3(params, tgt, blocks, true, overlap);
 
-    if (params.version == 1) {
-        status = LoadSrcTgtVersion1(params, tgt, blocks, params.buffer, params.fd);
-    } else if (params.version == 2) {
-        status = LoadSrcTgtVersion2(params, tgt, blocks, params.buffer, params.fd,
-                params.stashbase, nullptr);
-    } else if (params.version >= 3) {
-        status = LoadSrcTgtVersion3(params, tgt, blocks, true, overlap);
-    }
+  if (status == -1) {
+    LOG(ERROR) << "failed to read blocks for move";
+    return -1;
+  }
 
-    if (status == -1) {
-        LOG(ERROR) << "failed to read blocks for move";
-        return -1;
-    }
+  if (status == 0) {
+    params.foundwrites = true;
+  } else if (params.foundwrites) {
+    LOG(WARNING) << "warning: commands executed out of order [" << params.cmdname << "]";
+  }
 
+  if (params.canwrite) {
     if (status == 0) {
-        params.foundwrites = true;
-    } else if (params.foundwrites) {
-        LOG(WARNING) << "warning: commands executed out of order [" << params.cmdname << "]";
+      LOG(INFO) << "  moving " << blocks << " blocks";
+
+      if (WriteBlocks(tgt, params.buffer, params.fd) == -1) {
+        return -1;
+      }
+    } else {
+      LOG(INFO) << "skipping " << blocks << " already moved blocks";
     }
+  }
 
-    if (params.canwrite) {
-        if (status == 0) {
-            LOG(INFO) << "  moving " << blocks << " blocks";
+  if (!params.freestash.empty()) {
+    FreeStash(params.stashbase, params.freestash);
+    params.freestash.clear();
+  }
 
-            if (WriteBlocks(tgt, params.buffer, params.fd) == -1) {
-                return -1;
-            }
-        } else {
-            LOG(INFO) << "skipping " << blocks << " already moved blocks";
-        }
+  params.written += tgt.size;
 
-    }
-
-    if (!params.freestash.empty()) {
-        FreeStash(params.stashbase, params.freestash);
-        params.freestash.clear();
-    }
-
-    params.written += tgt.size;
-
-    return 0;
+  return 0;
 }
 
 static int PerformCommandStash(CommandParameters& params) {
-    return SaveStash(params, params.stashbase, params.buffer, params.fd,
-            (params.version >= 3));
+  // <stash_id> <src_range>
+  if (params.cpos + 1 >= params.tokens.size()) {
+    LOG(ERROR) << "missing id and/or src range fields in stash command";
+    return -1;
+  }
+
+  const std::string& id = params.tokens[params.cpos++];
+  size_t blocks = 0;
+  if (LoadStash(params, id, true, &blocks, params.buffer, false) == 0) {
+    // Stash file already exists and has expected contents. Do not read from source again, as the
+    // source may have been already overwritten during a previous attempt.
+    return 0;
+  }
+
+  RangeSet src = parse_range(params.tokens[params.cpos++]);
+
+  allocate(src.size * BLOCKSIZE, params.buffer);
+  if (ReadBlocks(src, params.buffer, params.fd) == -1) {
+    return -1;
+  }
+  blocks = src.size;
+  stash_map[id] = src;
+
+  if (VerifyBlocks(id, params.buffer, blocks, true) != 0) {
+    // Source blocks have unexpected contents. If we actually need this data later, this is an
+    // unrecoverable error. However, the command that uses the data may have already completed
+    // previously, so the possible failure will occur during source block verification.
+    LOG(ERROR) << "failed to load source blocks for stash " << id;
+    return 0;
+  }
+
+  // In verify mode, we don't need to stash any blocks.
+  if (!params.canwrite) {
+    return 0;
+  }
+
+  LOG(INFO) << "stashing " << blocks << " blocks to " << id;
+  params.stashed += blocks;
+  return WriteStash(params.stashbase, id, blocks, params.buffer, false, nullptr);
 }
 
 static int PerformCommandFree(CommandParameters& params) {
-    // <stash_id>
-    if (params.cpos >= params.tokens.size()) {
-        LOG(ERROR) << "missing stash id in free command";
-        return -1;
-    }
+  // <stash_id>
+  if (params.cpos >= params.tokens.size()) {
+    LOG(ERROR) << "missing stash id in free command";
+    return -1;
+  }
 
-    const std::string& id = params.tokens[params.cpos++];
+  const std::string& id = params.tokens[params.cpos++];
+  stash_map.erase(id);
 
-    if (stash_map.find(id) != stash_map.end()) {
-        stash_map.erase(id);
-    }
+  if (params.createdstash || params.canwrite) {
+    return FreeStash(params.stashbase, id);
+  }
 
-    if (params.createdstash || params.canwrite) {
-        return FreeStash(params.stashbase, id);
-    }
-
-    return 0;
+  return 0;
 }
 
 static int PerformCommandZero(CommandParameters& params) {
@@ -1339,15 +1284,7 @@
     RangeSet tgt;
     size_t blocks = 0;
     bool overlap = false;
-    int status = 0;
-    if (params.version == 1) {
-        status = LoadSrcTgtVersion1(params, tgt, blocks, params.buffer, params.fd);
-    } else if (params.version == 2) {
-        status = LoadSrcTgtVersion2(params, tgt, blocks, params.buffer, params.fd,
-                params.stashbase, nullptr);
-    } else if (params.version >= 3) {
-        status = LoadSrcTgtVersion3(params, tgt, blocks, false, overlap);
-    }
+    int status = LoadSrcTgtVersion3(params, tgt, blocks, false, overlap);
 
     if (status == -1) {
         LOG(ERROR) << "failed to read blocks for diff";
@@ -1473,301 +1410,281 @@
 static Value* PerformBlockImageUpdate(const char* name, State* state,
                                       const std::vector<std::unique_ptr<Expr>>& argv,
                                       const Command* commands, size_t cmdcount, bool dryrun) {
-    CommandParameters params = {};
-    params.canwrite = !dryrun;
+  CommandParameters params = {};
+  params.canwrite = !dryrun;
 
-    LOG(INFO) << "performing " << (dryrun ? "verification" : "update");
-    if (state->is_retry) {
-        is_retry = true;
-        LOG(INFO) << "This update is a retry.";
+  LOG(INFO) << "performing " << (dryrun ? "verification" : "update");
+  if (state->is_retry) {
+    is_retry = true;
+    LOG(INFO) << "This update is a retry.";
+  }
+  if (argv.size() != 4) {
+    ErrorAbort(state, kArgsParsingFailure, "block_image_update expects 4 arguments, got %zu",
+               argv.size());
+    return StringValue("");
+  }
+
+  std::vector<std::unique_ptr<Value>> args;
+  if (!ReadValueArgs(state, argv, &args)) {
+    return nullptr;
+  }
+
+  const Value* blockdev_filename = args[0].get();
+  const Value* transfer_list_value = args[1].get();
+  const Value* new_data_fn = args[2].get();
+  const Value* patch_data_fn = args[3].get();
+
+  if (blockdev_filename->type != VAL_STRING) {
+    ErrorAbort(state, kArgsParsingFailure, "blockdev_filename argument to %s must be string", name);
+    return StringValue("");
+  }
+  if (transfer_list_value->type != VAL_BLOB) {
+    ErrorAbort(state, kArgsParsingFailure, "transfer_list argument to %s must be blob", name);
+    return StringValue("");
+  }
+  if (new_data_fn->type != VAL_STRING) {
+    ErrorAbort(state, kArgsParsingFailure, "new_data_fn argument to %s must be string", name);
+    return StringValue("");
+  }
+  if (patch_data_fn->type != VAL_STRING) {
+    ErrorAbort(state, kArgsParsingFailure, "patch_data_fn argument to %s must be string", name);
+    return StringValue("");
+  }
+
+  UpdaterInfo* ui = static_cast<UpdaterInfo*>(state->cookie);
+  if (ui == nullptr) {
+    return StringValue("");
+  }
+
+  FILE* cmd_pipe = ui->cmd_pipe;
+  ZipArchiveHandle za = ui->package_zip;
+
+  if (cmd_pipe == nullptr || za == nullptr) {
+    return StringValue("");
+  }
+
+  ZipString path_data(patch_data_fn->data.c_str());
+  ZipEntry patch_entry;
+  if (FindEntry(za, path_data, &patch_entry) != 0) {
+    LOG(ERROR) << name << "(): no file \"" << patch_data_fn->data << "\" in package";
+    return StringValue("");
+  }
+
+  params.patch_start = ui->package_zip_addr + patch_entry.offset;
+  ZipString new_data(new_data_fn->data.c_str());
+  ZipEntry new_entry;
+  if (FindEntry(za, new_data, &new_entry) != 0) {
+    LOG(ERROR) << name << "(): no file \"" << new_data_fn->data << "\" in package";
+    return StringValue("");
+  }
+
+  params.fd.reset(TEMP_FAILURE_RETRY(ota_open(blockdev_filename->data.c_str(), O_RDWR)));
+  if (params.fd == -1) {
+    PLOG(ERROR) << "open \"" << blockdev_filename->data << "\" failed";
+    return StringValue("");
+  }
+
+  if (params.canwrite) {
+    params.nti.za = za;
+    params.nti.entry = new_entry;
+
+    pthread_mutex_init(&params.nti.mu, nullptr);
+    pthread_cond_init(&params.nti.cv, nullptr);
+    pthread_attr_t attr;
+    pthread_attr_init(&attr);
+    pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE);
+
+    int error = pthread_create(&params.thread, &attr, unzip_new_data, &params.nti);
+    if (error != 0) {
+      PLOG(ERROR) << "pthread_create failed";
+      return StringValue("");
     }
-    if (argv.size() != 4) {
-        ErrorAbort(state, kArgsParsingFailure, "block_image_update expects 4 arguments, got %zu",
-                   argv.size());
-        return StringValue("");
+  }
+
+  std::vector<std::string> lines = android::base::Split(transfer_list_value->data, "\n");
+  if (lines.size() < 2) {
+    ErrorAbort(state, kArgsParsingFailure, "too few lines in the transfer list [%zd]\n",
+               lines.size());
+    return StringValue("");
+  }
+
+  // First line in transfer list is the version number.
+  if (!android::base::ParseInt(lines[0], &params.version, 3, 4)) {
+    LOG(ERROR) << "unexpected transfer list version [" << lines[0] << "]";
+    return StringValue("");
+  }
+
+  LOG(INFO) << "blockimg version is " << params.version;
+
+  // Second line in transfer list is the total number of blocks we expect to write.
+  size_t total_blocks;
+  if (!android::base::ParseUint(lines[1], &total_blocks)) {
+    ErrorAbort(state, kArgsParsingFailure, "unexpected block count [%s]\n", lines[1].c_str());
+    return StringValue("");
+  }
+
+  if (total_blocks == 0) {
+    return StringValue("t");
+  }
+
+  size_t start = 2;
+  if (lines.size() < 4) {
+    ErrorAbort(state, kArgsParsingFailure, "too few lines in the transfer list [%zu]\n",
+               lines.size());
+    return StringValue("");
+  }
+
+  // Third line is how many stash entries are needed simultaneously.
+  LOG(INFO) << "maximum stash entries " << lines[2];
+
+  // Fourth line is the maximum number of blocks that will be stashed simultaneously
+  size_t stash_max_blocks;
+  if (!android::base::ParseUint(lines[3], &stash_max_blocks)) {
+    ErrorAbort(state, kArgsParsingFailure, "unexpected maximum stash blocks [%s]\n",
+               lines[3].c_str());
+    return StringValue("");
+  }
+
+  int res = CreateStash(state, stash_max_blocks, blockdev_filename->data, params.stashbase);
+  if (res == -1) {
+    return StringValue("");
+  }
+
+  params.createdstash = res;
+
+  start += 2;
+
+  // Build a map of the available commands
+  std::unordered_map<std::string, const Command*> cmd_map;
+  for (size_t i = 0; i < cmdcount; ++i) {
+    if (cmd_map.find(commands[i].name) != cmd_map.end()) {
+      LOG(ERROR) << "Error: command [" << commands[i].name << "] already exists in the cmd map.";
+      return StringValue(strdup(""));
+    }
+    cmd_map[commands[i].name] = &commands[i];
+  }
+
+  int rc = -1;
+
+  // Subsequent lines are all individual transfer commands
+  for (auto it = lines.cbegin() + start; it != lines.cend(); it++) {
+    const std::string& line(*it);
+    if (line.empty()) continue;
+
+    params.tokens = android::base::Split(line, " ");
+    params.cpos = 0;
+    params.cmdname = params.tokens[params.cpos++].c_str();
+    params.cmdline = line.c_str();
+
+    if (cmd_map.find(params.cmdname) == cmd_map.end()) {
+      LOG(ERROR) << "unexpected command [" << params.cmdname << "]";
+      goto pbiudone;
     }
 
-    std::vector<std::unique_ptr<Value>> args;
-    if (!ReadValueArgs(state, argv, &args)) {
-        return nullptr;
-    }
+    const Command* cmd = cmd_map[params.cmdname];
 
-    const Value* blockdev_filename = args[0].get();
-    const Value* transfer_list_value = args[1].get();
-    const Value* new_data_fn = args[2].get();
-    const Value* patch_data_fn = args[3].get();
-
-    if (blockdev_filename->type != VAL_STRING) {
-        ErrorAbort(state, kArgsParsingFailure, "blockdev_filename argument to %s must be string",
-                   name);
-        return StringValue("");
-    }
-    if (transfer_list_value->type != VAL_BLOB) {
-        ErrorAbort(state, kArgsParsingFailure, "transfer_list argument to %s must be blob", name);
-        return StringValue("");
-    }
-    if (new_data_fn->type != VAL_STRING) {
-        ErrorAbort(state, kArgsParsingFailure, "new_data_fn argument to %s must be string", name);
-        return StringValue("");
-    }
-    if (patch_data_fn->type != VAL_STRING) {
-        ErrorAbort(state, kArgsParsingFailure, "patch_data_fn argument to %s must be string",
-                   name);
-        return StringValue("");
-    }
-
-    UpdaterInfo* ui = static_cast<UpdaterInfo*>(state->cookie);
-    if (ui == nullptr) {
-        return StringValue("");
-    }
-
-    FILE* cmd_pipe = ui->cmd_pipe;
-    ZipArchiveHandle za = ui->package_zip;
-
-    if (cmd_pipe == nullptr || za == nullptr) {
-        return StringValue("");
-    }
-
-    ZipString path_data(patch_data_fn->data.c_str());
-    ZipEntry patch_entry;
-    if (FindEntry(za, path_data, &patch_entry) != 0) {
-        LOG(ERROR) << name << "(): no file \"" << patch_data_fn->data << "\" in package";
-        return StringValue("");
-    }
-
-    params.patch_start = ui->package_zip_addr + patch_entry.offset;
-    ZipString new_data(new_data_fn->data.c_str());
-    ZipEntry new_entry;
-    if (FindEntry(za, new_data, &new_entry) != 0) {
-        LOG(ERROR) << name << "(): no file \"" << new_data_fn->data << "\" in package";
-        return StringValue("");
-    }
-
-    params.fd.reset(TEMP_FAILURE_RETRY(ota_open(blockdev_filename->data.c_str(), O_RDWR)));
-    if (params.fd == -1) {
-        PLOG(ERROR) << "open \"" << blockdev_filename->data << "\" failed";
-        return StringValue("");
+    if (cmd->f != nullptr && cmd->f(params) == -1) {
+      LOG(ERROR) << "failed to execute command [" << line << "]";
+      goto pbiudone;
     }
 
     if (params.canwrite) {
-        params.nti.za = za;
-        params.nti.entry = new_entry;
-
-        pthread_mutex_init(&params.nti.mu, nullptr);
-        pthread_cond_init(&params.nti.cv, nullptr);
-        pthread_attr_t attr;
-        pthread_attr_init(&attr);
-        pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE);
-
-        int error = pthread_create(&params.thread, &attr, unzip_new_data, &params.nti);
-        if (error != 0) {
-            PLOG(ERROR) << "pthread_create failed";
-            return StringValue("");
-        }
-    }
-
-    std::vector<std::string> lines = android::base::Split(transfer_list_value->data, "\n");
-    if (lines.size() < 2) {
-        ErrorAbort(state, kArgsParsingFailure, "too few lines in the transfer list [%zd]\n",
-                   lines.size());
-        return StringValue("");
-    }
-
-    // First line in transfer list is the version number
-    if (!android::base::ParseInt(lines[0], &params.version, 1, 4)) {
-        LOG(ERROR) << "unexpected transfer list version [" << lines[0] << "]";
-        return StringValue("");
-    }
-
-    LOG(INFO) << "blockimg version is " << params.version;
-
-    // Second line in transfer list is the total number of blocks we expect to write
-    size_t total_blocks;
-    if (!android::base::ParseUint(lines[1], &total_blocks)) {
-        ErrorAbort(state, kArgsParsingFailure, "unexpected block count [%s]\n", lines[1].c_str());
-        return StringValue("");
-    }
-
-    if (total_blocks == 0) {
-        return StringValue("t");
-    }
-
-    size_t start = 2;
-    if (params.version >= 2) {
-        if (lines.size() < 4) {
-          ErrorAbort(state, kArgsParsingFailure, "too few lines in the transfer list [%zu]\n",
-                     lines.size());
-          return StringValue("");
-        }
-
-        // Third line is how many stash entries are needed simultaneously
-        LOG(INFO) << "maximum stash entries " << lines[2];
-
-        // Fourth line is the maximum number of blocks that will be stashed simultaneously
-        size_t stash_max_blocks;
-        if (!android::base::ParseUint(lines[3], &stash_max_blocks)) {
-            ErrorAbort(state, kArgsParsingFailure, "unexpected maximum stash blocks [%s]\n",
-                       lines[3].c_str());
-            return StringValue("");
-        }
-
-        int res = CreateStash(state, stash_max_blocks, blockdev_filename->data, params.stashbase);
-        if (res == -1) {
-            return StringValue("");
-        }
-
-        params.createdstash = res;
-
-        start += 2;
-    }
-
-    // Build a map of the available commands
-    std::unordered_map<std::string, const Command*> cmd_map;
-    for (size_t i = 0; i < cmdcount; ++i) {
-        if (cmd_map.find(commands[i].name) != cmd_map.end()) {
-            LOG(ERROR) << "Error: command [" << commands[i].name
-                       << "] already exists in the cmd map.";
-            return StringValue(strdup(""));
-        }
-        cmd_map[commands[i].name] = &commands[i];
-    }
-
-    int rc = -1;
-
-    // Subsequent lines are all individual transfer commands
-    for (auto it = lines.cbegin() + start; it != lines.cend(); it++) {
-        const std::string& line(*it);
-        if (line.empty()) continue;
-
-        params.tokens = android::base::Split(line, " ");
-        params.cpos = 0;
-        params.cmdname = params.tokens[params.cpos++].c_str();
-        params.cmdline = line.c_str();
-
-        if (cmd_map.find(params.cmdname) == cmd_map.end()) {
-            LOG(ERROR) << "unexpected command [" << params.cmdname << "]";
-            goto pbiudone;
-        }
-
-        const Command* cmd = cmd_map[params.cmdname];
-
-        if (cmd->f != nullptr && cmd->f(params) == -1) {
-            LOG(ERROR) << "failed to execute command [" << line << "]";
-            goto pbiudone;
-        }
-
-        if (params.canwrite) {
-            if (ota_fsync(params.fd) == -1) {
-                failure_type = kFsyncFailure;
-                PLOG(ERROR) << "fsync failed";
-                goto pbiudone;
-            }
-            fprintf(cmd_pipe, "set_progress %.4f\n",
-                    static_cast<double>(params.written) / total_blocks);
-            fflush(cmd_pipe);
-        }
-    }
-
-    if (params.canwrite) {
-        pthread_join(params.thread, nullptr);
-
-        LOG(INFO) << "wrote " << params.written << " blocks; expected " << total_blocks;
-        LOG(INFO) << "stashed " << params.stashed << " blocks";
-        LOG(INFO) << "max alloc needed was " << params.buffer.size();
-
-        const char* partition = strrchr(blockdev_filename->data.c_str(), '/');
-        if (partition != nullptr && *(partition + 1) != 0) {
-            fprintf(cmd_pipe, "log bytes_written_%s: %zu\n", partition + 1,
-                    params.written * BLOCKSIZE);
-            fprintf(cmd_pipe, "log bytes_stashed_%s: %zu\n", partition + 1,
-                    params.stashed * BLOCKSIZE);
-            fflush(cmd_pipe);
-        }
-        // Delete stash only after successfully completing the update, as it
-        // may contain blocks needed to complete the update later.
-        DeleteStash(params.stashbase);
-    } else {
-        LOG(INFO) << "verified partition contents; update may be resumed";
-    }
-
-    rc = 0;
-
-pbiudone:
-    if (ota_fsync(params.fd) == -1) {
+      if (ota_fsync(params.fd) == -1) {
         failure_type = kFsyncFailure;
         PLOG(ERROR) << "fsync failed";
+        goto pbiudone;
+      }
+      fprintf(cmd_pipe, "set_progress %.4f\n", static_cast<double>(params.written) / total_blocks);
+      fflush(cmd_pipe);
     }
-    // params.fd will be automatically closed because it's a unique_fd.
+  }
 
-    // Only delete the stash if the update cannot be resumed, or it's
-    // a verification run and we created the stash.
-    if (params.isunresumable || (!params.canwrite && params.createdstash)) {
-        DeleteStash(params.stashbase);
+  if (params.canwrite) {
+    pthread_join(params.thread, nullptr);
+
+    LOG(INFO) << "wrote " << params.written << " blocks; expected " << total_blocks;
+    LOG(INFO) << "stashed " << params.stashed << " blocks";
+    LOG(INFO) << "max alloc needed was " << params.buffer.size();
+
+    const char* partition = strrchr(blockdev_filename->data.c_str(), '/');
+    if (partition != nullptr && *(partition + 1) != 0) {
+      fprintf(cmd_pipe, "log bytes_written_%s: %zu\n", partition + 1, params.written * BLOCKSIZE);
+      fprintf(cmd_pipe, "log bytes_stashed_%s: %zu\n", partition + 1, params.stashed * BLOCKSIZE);
+      fflush(cmd_pipe);
     }
+    // Delete stash only after successfully completing the update, as it may contain blocks needed
+    // to complete the update later.
+    DeleteStash(params.stashbase);
+  } else {
+    LOG(INFO) << "verified partition contents; update may be resumed";
+  }
 
-    if (failure_type != kNoCause && state->cause_code == kNoCause) {
-        state->cause_code = failure_type;
-    }
+  rc = 0;
 
-    return StringValue(rc == 0 ? "t" : "");
+pbiudone:
+  if (ota_fsync(params.fd) == -1) {
+    failure_type = kFsyncFailure;
+    PLOG(ERROR) << "fsync failed";
+  }
+  // params.fd will be automatically closed because it's a unique_fd.
+
+  // Only delete the stash if the update cannot be resumed, or it's a verification run and we
+  // created the stash.
+  if (params.isunresumable || (!params.canwrite && params.createdstash)) {
+    DeleteStash(params.stashbase);
+  }
+
+  if (failure_type != kNoCause && state->cause_code == kNoCause) {
+    state->cause_code = failure_type;
+  }
+
+  return StringValue(rc == 0 ? "t" : "");
 }
 
-// The transfer list is a text file containing commands to
-// transfer data from one place to another on the target
-// partition.  We parse it and execute the commands in order:
-//
-//    zero [rangeset]
-//      - fill the indicated blocks with zeros
-//
-//    new [rangeset]
-//      - fill the blocks with data read from the new_data file
-//
-//    erase [rangeset]
-//      - mark the given blocks as empty
-//
-//    move <...>
-//    bsdiff <patchstart> <patchlen> <...>
-//    imgdiff <patchstart> <patchlen> <...>
-//      - read the source blocks, apply a patch (or not in the
-//        case of move), write result to target blocks.  bsdiff or
-//        imgdiff specifies the type of patch; move means no patch
-//        at all.
-//
-//        The format of <...> differs between versions 1 and 2;
-//        see the LoadSrcTgtVersion{1,2}() functions for a
-//        description of what's expected.
-//
-//    stash <stash_id> <src_range>
-//      - (version 2+ only) load the given source range and stash
-//        the data in the given slot of the stash table.
-//
-//    free <stash_id>
-//      - (version 3+ only) free the given stash data.
-//
-// The creator of the transfer list will guarantee that no block
-// is read (ie, used as the source for a patch or move) after it
-// has been written.
-//
-// In version 2, the creator will guarantee that a given stash is
-// loaded (with a stash command) before it's used in a
-// move/bsdiff/imgdiff command.
-//
-// Within one command the source and target ranges may overlap so
-// in general we need to read the entire source into memory before
-// writing anything to the target blocks.
-//
-// All the patch data is concatenated into one patch_data file in
-// the update package.  It must be stored uncompressed because we
-// memory-map it in directly from the archive.  (Since patches are
-// already compressed, we lose very little by not compressing
-// their concatenation.)
-//
-// In version 3, commands that read data from the partition (i.e.
-// move/bsdiff/imgdiff/stash) have one or more additional hashes
-// before the range parameters, which are used to check if the
-// command has already been completed and verify the integrity of
-// the source data.
-
+/**
+ * The transfer list is a text file containing commands to transfer data from one place to another
+ * on the target partition. We parse it and execute the commands in order:
+ *
+ *    zero [rangeset]
+ *      - Fill the indicated blocks with zeros.
+ *
+ *    new [rangeset]
+ *      - Fill the blocks with data read from the new_data file.
+ *
+ *    erase [rangeset]
+ *      - Mark the given blocks as empty.
+ *
+ *    move <...>
+ *    bsdiff <patchstart> <patchlen> <...>
+ *    imgdiff <patchstart> <patchlen> <...>
+ *      - Read the source blocks, apply a patch (or not in the case of move), write result to target
+ *      blocks.  bsdiff or imgdiff specifies the type of patch; move means no patch at all.
+ *
+ *        See the comments in LoadSrcTgtVersion3() for a description of the <...> format.
+ *
+ *    stash <stash_id> <src_range>
+ *      - Load the given source range and stash the data in the given slot of the stash table.
+ *
+ *    free <stash_id>
+ *      - Free the given stash data.
+ *
+ * The creator of the transfer list will guarantee that no block is read (ie, used as the source for
+ * a patch or move) after it has been written.
+ *
+ * The creator will guarantee that a given stash is loaded (with a stash command) before it's used
+ * in a move/bsdiff/imgdiff command.
+ *
+ * Within one command the source and target ranges may overlap so in general we need to read the
+ * entire source into memory before writing anything to the target blocks.
+ *
+ * All the patch data is concatenated into one patch_data file in the update package. It must be
+ * stored uncompressed because we memory-map it in directly from the archive. (Since patches are
+ * already compressed, we lose very little by not compressing their concatenation.)
+ *
+ * Commands that read data from the partition (i.e. move/bsdiff/imgdiff/stash) have one or more
+ * additional hashes before the range parameters, which are used to check if the command has already
+ * been completed and verify the integrity of the source data.
+ */
 Value* BlockImageVerifyFn(const char* name, State* state,
                           const std::vector<std::unique_ptr<Expr>>& argv) {
     // Commands which are not tested are set to nullptr to skip them completely
diff --git a/updater/updater.cpp b/updater/updater.cpp
index 0693cbd..c09e267 100644
--- a/updater/updater.cpp
+++ b/updater/updater.cpp
@@ -185,7 +185,7 @@
         // Parse the error code in abort message.
         // Example: "E30: This package is for bullhead devices."
         if (!line.empty() && line[0] == 'E') {
-          if (sscanf(line.c_str(), "E%u: ", &state.error_code) != 1) {
+          if (sscanf(line.c_str(), "E%d: ", &state.error_code) != 1) {
             LOG(ERROR) << "Failed to parse error code: [" << line << "]";
           }
         }
diff --git a/verifier.cpp b/verifier.cpp
index 8be6da0..2ef9c4c 100644
--- a/verifier.cpp
+++ b/verifier.cpp
@@ -376,7 +376,7 @@
 }
 
 struct BNDeleter {
-  void operator()(BIGNUM* bn) {
+  void operator()(BIGNUM* bn) const {
     BN_free(bn);
   }
 };
diff --git a/verifier.h b/verifier.h
index 6bee749..6fa8f2b 100644
--- a/verifier.h
+++ b/verifier.h
@@ -26,13 +26,13 @@
 #include <openssl/sha.h>
 
 struct RSADeleter {
-  void operator()(RSA* rsa) {
+  void operator()(RSA* rsa) const {
     RSA_free(rsa);
   }
 };
 
 struct ECKEYDeleter {
-  void operator()(EC_KEY* ec_key) {
+  void operator()(EC_KEY* ec_key) const {
     EC_KEY_free(ec_key);
   }
 };
diff --git a/wear_touch.cpp b/wear_touch.cpp
index cf33daa..e2ab44d 100644
--- a/wear_touch.cpp
+++ b/wear_touch.cpp
@@ -118,7 +118,7 @@
 }
 
 void* WearSwipeDetector::touch_thread(void* cookie) {
-    ((WearSwipeDetector*)cookie)->run();
+    (static_cast<WearSwipeDetector*>(cookie))->run();
     return NULL;
 }