diff --git a/src/startup_ch32v003.S b/src/startup_ch32v003.S
index b5d9f7e..c6b47b9 100644
--- a/src/startup_ch32v003.S
+++ b/src/startup_ch32v003.S
@@ -233,7 +233,7 @@ handle_reset:
     /* SystemInit: does stuff like clock setup, PLL cnofig, Periph reset. */
 
     /* This mcu and microprocessor only has "M-Mode" or machine mode */
-    /* The other modes, U(user) and S(???) aren't availble. */
+    /* The other modes, U(user) and S(Supervisor) aren't availble. */
     /* MEPC: Machine Exception Program Counter.*/
     /* Jump's and links(ra --> return address) to SystemInit */
     jal   SystemInit