diff --git a/tests/component/bootloader_message_test.cpp b/tests/component/bootloader_message_test.cpp
index b005d19..95d875e 100644
--- a/tests/component/bootloader_message_test.cpp
+++ b/tests/component/bootloader_message_test.cpp
@@ -15,6 +15,7 @@
  */
 
 #include <string>
+#include <string_view>
 #include <vector>
 
 #include <android-base/file.h>
@@ -22,6 +23,10 @@
 #include <bootloader_message/bootloader_message.h>
 #include <gtest/gtest.h>
 
+using namespace std::string_literals;
+
+extern void SetMiscBlockDeviceForTest(std::string_view misc_device);
+
 TEST(BootloaderMessageTest, read_and_write_bootloader_message) {
   TemporaryFile temp_misc;
 
@@ -114,3 +119,36 @@
             std::string(boot.reserved, sizeof(boot.reserved)));
 }
 
+TEST(BootloaderMessageTest, WriteMiscPartitionVendorSpace) {
+  TemporaryFile temp_misc;
+  ASSERT_TRUE(android::base::WriteStringToFile(std::string(4096, '\x00'), temp_misc.path));
+  SetMiscBlockDeviceForTest(temp_misc.path);
+
+  constexpr std::string_view kTestMessage = "kTestMessage";
+  std::string err;
+  ASSERT_TRUE(WriteMiscPartitionVendorSpace(kTestMessage.data(), kTestMessage.size(), 0, &err));
+
+  std::string message;
+  message.resize(kTestMessage.size());
+  ASSERT_TRUE(ReadMiscPartitionVendorSpace(message.data(), message.size(), 0, &err));
+  ASSERT_EQ(kTestMessage, message);
+
+  // Write with an offset.
+  ASSERT_TRUE(WriteMiscPartitionVendorSpace("\x00\x00", 2, 5, &err));
+  ASSERT_TRUE(ReadMiscPartitionVendorSpace(message.data(), message.size(), 0, &err));
+  ASSERT_EQ("kTest\x00\x00ssage"s, message);
+
+  // Write with the right size.
+  auto start_offset =
+      WIPE_PACKAGE_OFFSET_IN_MISC - VENDOR_SPACE_OFFSET_IN_MISC - kTestMessage.size();
+  ASSERT_TRUE(
+      WriteMiscPartitionVendorSpace(kTestMessage.data(), kTestMessage.size(), start_offset, &err));
+
+  // Out-of-bound write.
+  ASSERT_FALSE(WriteMiscPartitionVendorSpace(kTestMessage.data(), kTestMessage.size(),
+                                             start_offset + 1, &err));
+
+  // Message won't fit.
+  std::string long_message(WIPE_PACKAGE_OFFSET_IN_MISC - VENDOR_SPACE_OFFSET_IN_MISC + 1, 'a');
+  ASSERT_FALSE(WriteMiscPartitionVendorSpace(long_message.data(), long_message.size(), 0, &err));
+}