diff --git a/include/ec_commands.h b/include/ec_commands.h
index 660a432b35..45a2d7b30a 100644
--- a/include/ec_commands.h
+++ b/include/ec_commands.h
@@ -3807,6 +3807,13 @@ struct ec_response_usb_pd_mux_info {
  */
 #define EC_CMD_BLOB 0x200
 
+/*****************************************************************************/
+/*
+ * Reserve a range of host commands for the CR51 firmware.
+ */
+#define EC_CMD_CR51_BASE 0x300
+#define EC_CMD_CR51_LAST 0x3FF
+
 /*****************************************************************************/
 /*
  * Reserve a range of host commands for board-specific, experimental, or