diff --git a/bootloader_message/bootloader_message.cpp b/bootloader_message/bootloader_message.cpp
index e0c95d22..16e8df14 100644
--- a/bootloader_message/bootloader_message.cpp
+++ b/bootloader_message/bootloader_message.cpp
@@ -164,6 +164,19 @@ bool write_bootloader_message(const std::vector<std::string>& options, std::stri
   return write_bootloader_message(boot, err);
 }
 
+bool write_reboot_bootloader(std::string* err) {
+  bootloader_message boot;
+  if (!read_bootloader_message(&boot, err)) {
+    return false;
+  }
+  if (boot.command[0] != '\0') {
+    *err = "Bootloader command pending.";
+    return false;
+  }
+  strlcpy(boot.command, "bootonce-bootloader", sizeof(boot.command));
+  return write_bootloader_message(boot, err);
+}
+
 bool read_wipe_package(std::string* package_data, size_t size, std::string* err) {
   package_data->resize(size);
   return read_misc_partition(&(*package_data)[0], size, WIPE_PACKAGE_OFFSET_IN_MISC, err);
@@ -174,6 +187,11 @@ bool write_wipe_package(const std::string& package_data, std::string* err) {
                               WIPE_PACKAGE_OFFSET_IN_MISC, err);
 }
 
+extern "C" bool write_reboot_bootloader(void) {
+  std::string err;
+  return write_reboot_bootloader(&err);
+}
+
 extern "C" bool write_bootloader_message(const char* options) {
   std::string err;
   return write_bootloader_message({options}, &err);
diff --git a/bootloader_message/include/bootloader_message/bootloader_message.h b/bootloader_message/include/bootloader_message/bootloader_message.h
index f343c64a..75d2acaf 100644
--- a/bootloader_message/include/bootloader_message/bootloader_message.h
+++ b/bootloader_message/include/bootloader_message/bootloader_message.h
@@ -184,6 +184,9 @@ bool write_bootloader_message(const bootloader_message& boot, std::string* err);
 bool write_bootloader_message(const std::vector<std::string>& options, std::string* err);
 bool clear_bootloader_message(std::string* err);
 
+// Writes the reboot-bootloader reboot reason to the bootloader_message.
+bool write_reboot_bootloader(std::string* err);
+
 bool read_wipe_package(std::string* package_data, size_t size, std::string* err);
 bool write_wipe_package(const std::string& package_data, std::string* err);
 
@@ -193,6 +196,7 @@ bool write_wipe_package(const std::string& package_data, std::string* err);
 
 // C Interface.
 bool write_bootloader_message(const char* options);
+bool write_reboot_bootloader(void);
 
 #endif  // ifdef __cplusplus