diff --git a/SBIN/SHELL.S.HIS.txt b/SBIN/SHELL.S.HIS.txt
index e3f838b5..c18f09b7 100644
--- a/SBIN/SHELL.S.HIS.txt
+++ b/SBIN/SHELL.S.HIS.txt
@@ -112,6 +112,8 @@ History.GetPrev	ldy #hCmdHistory
 				tay
 				sec
 				adc (ZPPTR1),y
+				bcs History.RTS			out of buffer
+				
 				ldy #CmdHistory.IDX
 				cmp (pData),y
 				bne .1					reached current index