diff --git a/src/ble-pybricks-service/protocol.ts b/src/ble-pybricks-service/protocol.ts
index 34e5bde0..893ac75f 100644
--- a/src/ble-pybricks-service/protocol.ts
+++ b/src/ble-pybricks-service/protocol.ts
@@ -26,6 +26,8 @@ export enum CommandType {
     WriteUserProgramMeta = 3,
     /** Request to write to user RAM. */
     WriteUserRam = 4,
+    /** Request to reboot in firmware update mode. */
+    ResetInUpdateMode = 5,
 }
 
 /**