diff --git a/Source/HBIOS/hbios.asm b/Source/HBIOS/hbios.asm
index 528164d2..a2e8fe00 100644
--- a/Source/HBIOS/hbios.asm
+++ b/Source/HBIOS/hbios.asm
@@ -7381,7 +7381,9 @@ FP_DETECT1:
 	; ATTEMPT TO CONFIRM WE HAVE A VALID PORT.  CREDIT TO STEPHEN
 	; COUSINS FOR THIS APPROACH.
 	LD	C,FPSW_IO		; ADR OF SWITCH PORT
+	EZ80_IO
 	IN	C,(C)			; READ IT USING IN (C)
+	EZ80_IO
 	IN	A,(FPSW_IO)		; READ IT USING IN (PORT)
 	CP	C			; PORT FLOATING ON MISMATCH
 	JR	NZ,FP_DETECT2		; NO H/W, SET FLAG
@@ -7427,6 +7429,7 @@ FP_GETSWITCHES:
 	LD	A,(FPSW_ACTIVE)		; SWITCHES ACTIVE?
 	OR	A			; SET FLAGS
 	RET	Z			; BAIL OUT IF NOT ACTIVE
+	EZ80_IO
 	IN	A,(FPSW_IO)		; READ SWITCHES
   #IF (FPSW_INV)
 	XOR	$FF			; INVERT BITS IF NEEDED