diff --git a/Source/HBIOS/cfg_sbc.asm b/Source/HBIOS/cfg_sbc.asm
index 8023fa6f..8e9813ea 100644
--- a/Source/HBIOS/cfg_sbc.asm
+++ b/Source/HBIOS/cfg_sbc.asm
@@ -93,5 +93,5 @@ BOOTTYPE	.EQU	BT_MENU		; BT_MENU (WAIT FOR KEYPRESS), BT_AUTO (BOOT_DEFAULT AFTE
 BOOT_TIMEOUT	.EQU	20		; APPROX TIMEOUT IN SECONDS FOR AUTOBOOT, 0 FOR IMMEDIATE
 BOOT_DEFAULT	.EQU	'Z'		; SELECTION TO INVOKE AT TIMEOUT
 
-PIOENABLE	.EQU	TRUE		; TRUE FOR ZILOG PIO SUPPORT
-PIOMODE		.EQU	PIOMODE_ZP		; PIOMODE_ZP=ECB-ZILOG PERIPHERALS BOARD PIOMODE_4P=ECB-4PIO
+PIOENABLE	.EQU	FALSE		; TRUE FOR ZILOG PIO SUPPORT
+PIOMODE		.EQU	PIOMODE_ZP	; PIOMODE_ZP=ECB-ZILOG PERIPHERALS BOARD PIOMODE_4P=ECB-4PIO
diff --git a/Source/HBIOS/hbios.asm b/Source/HBIOS/hbios.asm
index 7311ac95..56116b9c 100644
--- a/Source/HBIOS/hbios.asm
+++ b/Source/HBIOS/hbios.asm
@@ -1322,7 +1322,7 @@ CIO_ADDENT:
 ;	WORD	UNIT SPECIFIC DATA (TYPICALLY A DEVICE INSTANCE DATA ADDRESS)
 ;
 CIO_FNCNT	.EQU	7		; NUMBER OF CIO FUNCS (FOR RANGE CHECK)
-CIO_MAX		.EQU	16		; UP TO 16 UNITS
+CIO_MAX		.EQU	32		; UP TO 32 UNITS
 CIO_SIZ		.EQU	CIO_MAX * 4	; EACH ENTRY IS 4 BYTES
 ;	                                
 		.DB	CIO_FNCNT	; CIO FUNCTION COUNT (FOR RANGE CHECK)