diff --git a/constants/SP2000.inc b/constants/SP2000.inc
index 8a48c65..8f983b2 100644
--- a/constants/SP2000.inc
+++ b/constants/SP2000.inc
@@ -969,7 +969,7 @@ BootUpParams		EQU	#0E
 .Mask.UpdBios			EQU %0010'0000 * 256 + BootUpParams	;!TODO	; UPDATE BIOS
 .Mask.StartDelay		EQU %0001'1000 * 256 + BootUpParams		; START DELAY
 .Mask.Language			EQU %0000'0100 * 256 + BootUpParams		; LANGUAGE
-;.Mask.Reserved			EQU %0000'0010 * 256 + BootUpParams		; NOT USED
+.Mask.BootSound			EQU %0000'0010 * 256 + BootUpParams		; StartUp Sound
 .Mask.QuickStartROM		EQU %0000'0001 * 256 + BootUpParams		; QUICK START
 
 Typematic		EQU	#0F