diff --git a/Source/HBIOS/rf.asm b/Source/HBIOS/rf.asm
index f5fa1f55..30588a57 100644
--- a/Source/HBIOS/rf.asm
+++ b/Source/HBIOS/rf.asm
@@ -288,21 +288,9 @@ RF_WRSEC:
 ;
 ;
 RF_SETIO:
-	LD	A,(IY+RF_DEV)		; GET DEVICE NUM
-	OR	A			; SET FLAGS
-	JR	NZ,RF_SETIO1
-	LD	A,RF_U0IO
-	JR	RF_SETIO3
-RF_SETIO1:
-	DEC	A
-	JR	NZ,RF_SETIO2
-	LD	A,RF_U1IO
-	JR	RF_SETIO3
-RF_SETIO2:
-	CALL	PANIC			; INVALID UNIT
-RF_SETIO3:
-	LD	(RF_IO),A
-	RET
+	LD	A,(IY+RF_IOAD)		; GET THE IO PORT
+	LD	(RF_IO),A		; OF THE DEVICE WE
+	RET				; ARE WORKING ON
 ;
 ;
 ;