diff --git a/Source/HBIOS/usrrom.asm b/Source/HBIOS/usrrom.asm
index bbc54162..be9d80f4 100644
--- a/Source/HBIOS/usrrom.asm
+++ b/Source/HBIOS/usrrom.asm
@@ -44,7 +44,7 @@ COUT:	PUSH	AF
 	PUSH	DE
 	PUSH	HL
 	LD	B,01H
-	LD	C,0
+	LD	C,80H
 	LD	E,A
 	RST	08
 	POP	HL
@@ -59,7 +59,7 @@ CIN:	PUSH	BC
 	PUSH	DE
 	PUSH	HL
 	LD	B,00H
-	LD	C,00H
+	LD	C,80H
 	RST	08
 	LD	A,E
 	POP	HL