diff --git a/bootloader_message/bootloader_message.cpp b/bootloader_message/bootloader_message.cpp
index 9a56718..294b172 100644
--- a/bootloader_message/bootloader_message.cpp
+++ b/bootloader_message/bootloader_message.cpp
@@ -164,7 +164,13 @@
 }
 
 bool write_bootloader_message(const std::vector<std::string>& options, std::string* err) {
-  bootloader_message boot = {};
+  bootloader_message boot;
+  if (!read_bootloader_message(&boot, err)) {
+    return false;
+  }
+  // Zero out the entire fields.
+  memset(boot.command, 0, sizeof(boot.command));
+  memset(boot.recovery, 0, sizeof(boot.recovery));
   strlcpy(boot.command, "boot-recovery", sizeof(boot.command));
   strlcpy(boot.recovery, "recovery\n", sizeof(boot.recovery));
   for (const auto& s : options) {
diff --git a/bootloader_message/include/bootloader_message/bootloader_message.h b/bootloader_message/include/bootloader_message/bootloader_message.h
index b3d2182..437189e 100644
--- a/bootloader_message/include/bootloader_message/bootloader_message.h
+++ b/bootloader_message/include/bootloader_message/bootloader_message.h
@@ -193,7 +193,8 @@
 bool write_bootloader_message_to(const bootloader_message& boot,
                                  const std::string& misc_blk_device, std::string* err);
 
-// Write bootloader message (boots into recovery with the options) to BCB.
+// Write bootloader message (boots into recovery with the options) to BCB. Will
+// set command and recovery fields only.
 bool write_bootloader_message(const std::vector<std::string>& options, std::string* err);
 
 // Clear BCB.