diff --git a/Source/HBIOS/cfg_duo.asm b/Source/HBIOS/cfg_duo.asm
index 50994d4a..4843f81b 100644
--- a/Source/HBIOS/cfg_duo.asm
+++ b/Source/HBIOS/cfg_duo.asm
@@ -131,7 +131,7 @@ UARTOSC		.EQU	7372800		; UART: OSC FREQUENCY IN MHZ
 UARTINTS	.EQU	FALSE		; UART: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
 UARTCFG		.EQU	DEFSERCFG	; UART: LINE CONFIG FOR UART PORTS
 UARTCASSPD	.EQU	SER_300_8N1	; UART: ECB CASSETTE UART DEFAULT SPEED
-UARTSBC		.EQU	TRUE		; UART: AUTO-DETECT SBC/ZETA/DUO ONBOARD UART
+UARTSBC		.EQU	TRUE		; UART: AUTO-DETECT SBC/ZETA/DUO/NABU ONBOARD UART
 UARTSBCFORCE	.EQU	FALSE		; UART: FORCE DETECTION OF SBC UART (FOR SIMH)
 UARTAUX		.EQU	TRUE		; UART: AUTO-DETECT AUX UART
 UARTCAS		.EQU	FALSE		; UART: AUTO-DETECT ECB CASSETTE UART
@@ -139,7 +139,6 @@ UARTMFP		.EQU	FALSE		; UART: AUTO-DETECT MF/PIC UART
 UART4		.EQU	FALSE		; UART: AUTO-DETECT 4UART UART
 UARTRC		.EQU	FALSE		; UART: AUTO-DETECT RC UART
 UARTDUAL	.EQU	TRUE		; UART: AUTO-DETECT DUAL UART
-UARTNABU	.EQU	FALSE		; UART: AUTO-DETECT NABU UART
 ;
 ASCIENABLE	.EQU	FALSE		; ASCI: ENABLE Z180 ASCI SERIAL DRIVER (ASCI.ASM)
 ;
diff --git a/Source/HBIOS/cfg_dyno.asm b/Source/HBIOS/cfg_dyno.asm
index 42298316..dd3f3c05 100644
--- a/Source/HBIOS/cfg_dyno.asm
+++ b/Source/HBIOS/cfg_dyno.asm
@@ -139,7 +139,7 @@ UARTENABLE	.EQU	FALSE		; UART: ENABLE 8250/16550-LIKE SERIAL DRIVER (UART.ASM)
 UARTOSC		.EQU	1843200		; UART: OSC FREQUENCY IN MHZ
 UARTINTS	.EQU	FALSE		; UART: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
 UARTCFG		.EQU	DEFSERCFG | SER_RTS	; UART: LINE CONFIG FOR UART PORTS
-UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA/DUO ONBOARD UART
+UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA/DUO/NABU ONBOARD UART
 UARTSBCFORCE	.EQU	FALSE		; UART: FORCE DETECTION OF SBC UART (FOR SIMH)
 UARTAUX		.EQU	FALSE		; UART: AUTO-DETECT AUX UART
 UARTCAS		.EQU	FALSE		; UART: AUTO-DETECT ECB CASSETTE UART
@@ -147,7 +147,6 @@ UARTMFP		.EQU	FALSE		; UART: AUTO-DETECT MF/PIC UART
 UART4		.EQU	FALSE		; UART: AUTO-DETECT 4UART UART
 UARTRC		.EQU	TRUE		; UART: AUTO-DETECT RC UART
 UARTDUAL	.EQU	FALSE		; UART: AUTO-DETECT DUAL UART
-UARTNABU	.EQU	FALSE		; UART: AUTO-DETECT NABU UART
 ;
 ASCIENABLE	.EQU	TRUE		; ASCI: ENABLE Z180 ASCI SERIAL DRIVER (ASCI.ASM)
 ASCIINTS	.EQU	TRUE		; ASCI: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
diff --git a/Source/HBIOS/cfg_epitx.asm b/Source/HBIOS/cfg_epitx.asm
index 7ca40d09..4002c7d1 100644
--- a/Source/HBIOS/cfg_epitx.asm
+++ b/Source/HBIOS/cfg_epitx.asm
@@ -141,7 +141,7 @@ UARTENABLE	.EQU	TRUE		; UART: ENABLE 8250/16550-LIKE SERIAL DRIVER (UART.ASM)
 UARTOSC		.EQU	1843200		; UART: OSC FREQUENCY IN MHZ
 UARTINTS	.EQU	FALSE		; UART: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
 UARTCFG		.EQU	DEFSERCFG | SER_RTS	; UART: LINE CONFIG FOR UART PORTS
-UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA/DUO ONBOARD UART
+UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA/DUO/NABU ONBOARD UART
 UARTSBCFORCE	.EQU	FALSE		; UART: FORCE DETECTION OF SBC UART (FOR SIMH)
 UARTAUX		.EQU	FALSE		; UART: AUTO-DETECT AUX UART
 UARTCAS		.EQU	FALSE		; UART: AUTO-DETECT ECB CASSETTE UART
@@ -149,7 +149,6 @@ UARTMFP		.EQU	FALSE		; UART: AUTO-DETECT MF/PIC UART
 UART4		.EQU	FALSE		; UART: AUTO-DETECT 4UART UART
 UARTRC		.EQU	TRUE		; UART: AUTO-DETECT RC UART
 UARTDUAL	.EQU	FALSE		; UART: AUTO-DETECT DUAL UART
-UARTNABU	.EQU	FALSE		; UART: AUTO-DETECT NABU UART
 ;
 ASCIENABLE	.EQU	TRUE		; ASCI: ENABLE Z180 ASCI SERIAL DRIVER (ASCI.ASM)
 ASCIINTS	.EQU	TRUE		; ASCI: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
diff --git a/Source/HBIOS/cfg_heath.asm b/Source/HBIOS/cfg_heath.asm
index c3f4f10e..41f6cb6a 100644
--- a/Source/HBIOS/cfg_heath.asm
+++ b/Source/HBIOS/cfg_heath.asm
@@ -139,7 +139,7 @@ UARTENABLE	.EQU	TRUE		; UART: ENABLE 8250/16550-LIKE SERIAL DRIVER (UART.ASM)
 UARTOSC		.EQU	1843200		; UART: OSC FREQUENCY IN MHZ
 UARTINTS	.EQU	FALSE		; UART: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
 UARTCFG		.EQU	DEFSERCFG | SER_RTS	; UART: LINE CONFIG FOR UART PORTS
-UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA/DUO ONBOARD UART
+UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA/DUO/NABU ONBOARD UART
 UARTSBCFORCE	.EQU	FALSE		; UART: FORCE DETECTION OF SBC UART (FOR SIMH)
 UARTAUX		.EQU	FALSE		; UART: AUTO-DETECT AUX UART
 UARTCAS		.EQU	FALSE		; UART: AUTO-DETECT ECB CASSETTE UART
@@ -147,7 +147,6 @@ UARTMFP		.EQU	FALSE		; UART: AUTO-DETECT MF/PIC UART
 UART4		.EQU	FALSE		; UART: AUTO-DETECT 4UART UART
 UARTRC		.EQU	TRUE		; UART: AUTO-DETECT RC UART
 UARTDUAL	.EQU	FALSE		; UART: AUTO-DETECT DUAL UART
-UARTNABU	.EQU	FALSE		; UART: AUTO-DETECT NABU UART
 ;
 ASCIENABLE	.EQU	FALSE		; ASCI: ENABLE Z180 ASCI SERIAL DRIVER (ASCI.ASM)
 ;
diff --git a/Source/HBIOS/cfg_master.asm b/Source/HBIOS/cfg_master.asm
index 18fcd0c5..e10cda1d 100644
--- a/Source/HBIOS/cfg_master.asm
+++ b/Source/HBIOS/cfg_master.asm
@@ -169,7 +169,7 @@ UARTOSC		.EQU	1843200		; UART: OSC FREQUENCY IN MHZ
 UARTINTS	.EQU	FALSE		; UART: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
 UARTCFG		.EQU	DEFSERCFG	; UART: LINE CONFIG FOR UART PORTS
 UARTCASSPD	.EQU	SER_300_8N1	; UART: ECB CASSETTE UART DEFAULT SPEED
-UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA/DUO ONBOARD UART
+UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA/DUO/NABU ONBOARD UART
 UARTSBCFORCE	.EQU	FALSE		; UART: FORCE DETECTION OF SBC UART (FOR SIMH)
 UARTAUX		.EQU	FALSE		; UART: AUTO-DETECT AUX UART
 UARTCAS		.EQU	FALSE		; UART: AUTO-DETECT ECB CASSETTE UART
@@ -177,7 +177,6 @@ UARTMFP		.EQU	FALSE		; UART: AUTO-DETECT MF/PIC UART
 UART4		.EQU	FALSE		; UART: AUTO-DETECT 4UART UART
 UARTRC		.EQU	FALSE		; UART: AUTO-DETECT RC UART
 UARTDUAL	.EQU	FALSE		; UART: AUTO-DETECT DUAL UART
-UARTNABU	.EQU	FALSE		; UART: AUTO-DETECT NABU UART
 ;
 ASCIENABLE	.EQU	FALSE		; ASCI: ENABLE Z180 ASCI SERIAL DRIVER (ASCI.ASM)
 ASCIINTS	.EQU	TRUE		; ASCI: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
diff --git a/Source/HBIOS/cfg_mbc.asm b/Source/HBIOS/cfg_mbc.asm
index f767a352..bc37a51f 100644
--- a/Source/HBIOS/cfg_mbc.asm
+++ b/Source/HBIOS/cfg_mbc.asm
@@ -128,7 +128,7 @@ UARTOSC		.EQU	1843200		; UART: OSC FREQUENCY IN MHZ
 UARTINTS	.EQU	FALSE		; UART: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
 UARTCFG		.EQU	DEFSERCFG	; UART: LINE CONFIG FOR UART PORTS
 UARTCASSPD	.EQU	SER_300_8N1	; UART: ECB CASSETTE UART DEFAULT SPEED
-UARTSBC		.EQU	TRUE		; UART: AUTO-DETECT SBC/ZETA/DUO ONBOARD UART
+UARTSBC		.EQU	TRUE		; UART: AUTO-DETECT SBC/ZETA/DUO/NABU ONBOARD UART
 UARTSBCFORCE	.EQU	FALSE		; UART: FORCE DETECTION OF SBC UART (FOR SIMH)
 UARTAUX		.EQU	FALSE		; UART: AUTO-DETECT AUX UART
 UARTCAS		.EQU	FALSE		; UART: AUTO-DETECT ECB CASSETTE UART
@@ -136,7 +136,6 @@ UARTMFP		.EQU	FALSE		; UART: AUTO-DETECT MF/PIC UART
 UART4		.EQU	FALSE		; UART: AUTO-DETECT 4UART UART
 UARTRC		.EQU	FALSE		; UART: AUTO-DETECT RC UART
 UARTDUAL	.EQU	TRUE		; UART: AUTO-DETECT DUAL UART
-UARTNABU	.EQU	FALSE		; UART: AUTO-DETECT NABU UART
 ;
 ASCIENABLE	.EQU	FALSE		; ASCI: ENABLE Z180 ASCI SERIAL DRIVER (ASCI.ASM)
 ;
diff --git a/Source/HBIOS/cfg_mk4.asm b/Source/HBIOS/cfg_mk4.asm
index 39214bb6..691440e6 100644
--- a/Source/HBIOS/cfg_mk4.asm
+++ b/Source/HBIOS/cfg_mk4.asm
@@ -133,7 +133,7 @@ UARTOSC		.EQU	1843200		; UART: OSC FREQUENCY IN MHZ
 UARTINTS	.EQU	FALSE		; UART: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
 UARTCFG		.EQU	DEFSERCFG	; UART: LINE CONFIG FOR UART PORTS
 UARTCASSPD	.EQU	SER_300_8N1	; UART: ECB CASSETTE UART DEFAULT SPEED
-UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA/DUO ONBOARD UART
+UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA/DUO/NABU ONBOARD UART
 UARTSBCFORCE	.EQU	FALSE		; UART: FORCE DETECTION OF SBC UART (FOR SIMH)
 UARTAUX		.EQU	FALSE		; UART: AUTO-DETECT AUX UART
 UARTCAS		.EQU	TRUE		; UART: AUTO-DETECT ECB CASSETTE UART
@@ -141,7 +141,6 @@ UARTMFP		.EQU	FALSE		; UART: AUTO-DETECT MF/PIC UART
 UART4		.EQU	TRUE		; UART: AUTO-DETECT 4UART UART
 UARTRC		.EQU	FALSE		; UART: AUTO-DETECT RC UART
 UARTDUAL	.EQU	FALSE		; UART: AUTO-DETECT DUAL UART
-UARTNABU	.EQU	FALSE		; UART: AUTO-DETECT NABU UART
 ;
 ASCIENABLE	.EQU	TRUE		; ASCI: ENABLE Z180 ASCI SERIAL DRIVER (ASCI.ASM)
 ASCIINTS	.EQU	TRUE		; ASCI: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
diff --git a/Source/HBIOS/cfg_mon.asm b/Source/HBIOS/cfg_mon.asm
index 32db23b4..00f7b408 100644
--- a/Source/HBIOS/cfg_mon.asm
+++ b/Source/HBIOS/cfg_mon.asm
@@ -134,7 +134,7 @@ UARTENABLE	.EQU	FALSE		; UART: ENABLE 8250/16550-LIKE SERIAL DRIVER (UART.ASM)
 UARTOSC		.EQU	1843200		; UART: OSC FREQUENCY IN MHZ
 UARTINTS	.EQU	FALSE		; UART: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
 UARTCFG		.EQU	DEFSERCFG | SER_RTS	; UART: LINE CONFIG FOR UART PORTS
-UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA/DUO ONBOARD UART
+UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA/DUO/NABU ONBOARD UART
 UARTSBCFORCE	.EQU	FALSE		; UART: FORCE DETECTION OF SBC UART (FOR SIMH)
 UARTAUX		.EQU	FALSE		; UART: AUTO-DETECT AUX UART
 UARTCAS		.EQU	FALSE		; UART: AUTO-DETECT ECB CASSETTE UART
@@ -142,7 +142,6 @@ UARTMFP		.EQU	FALSE		; UART: AUTO-DETECT MF/PIC UART
 UART4		.EQU	FALSE		; UART: AUTO-DETECT 4UART UART
 UARTRC		.EQU	TRUE		; UART: AUTO-DETECT RC UART
 UARTDUAL	.EQU	FALSE		; UART: AUTO-DETECT DUAL UART
-UARTNABU	.EQU	FALSE		; UART: AUTO-DETECT NABU UART
 ;
 ASCIENABLE	.EQU	FALSE		; ASCI: ENABLE Z180 ASCI SERIAL DRIVER (ASCI.ASM)
 ;
diff --git a/Source/HBIOS/cfg_n8.asm b/Source/HBIOS/cfg_n8.asm
index 8ecb59e0..d810827d 100644
--- a/Source/HBIOS/cfg_n8.asm
+++ b/Source/HBIOS/cfg_n8.asm
@@ -135,7 +135,7 @@ UARTOSC		.EQU	1843200		; UART: OSC FREQUENCY IN MHZ
 UARTINTS	.EQU	FALSE		; UART: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
 UARTCFG		.EQU	DEFSERCFG	; UART: LINE CONFIG FOR UART PORTS
 UARTCASSPD	.EQU	SER_300_8N1	; UART: ECB CASSETTE UART DEFAULT SPEED
-UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA/DUO ONBOARD UART
+UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA/DUO/NABU ONBOARD UART
 UARTSBCFORCE	.EQU	FALSE		; UART: FORCE DETECTION OF SBC UART (FOR SIMH)
 UARTAUX		.EQU	FALSE		; UART: AUTO-DETECT AUX UART
 UARTCAS		.EQU	TRUE		; UART: AUTO-DETECT ECB CASSETTE UART
@@ -143,7 +143,6 @@ UARTMFP		.EQU	FALSE		; UART: AUTO-DETECT MF/PIC UART
 UART4		.EQU	TRUE		; UART: AUTO-DETECT 4UART UART
 UARTRC		.EQU	FALSE		; UART: AUTO-DETECT RC UART
 UARTDUAL	.EQU	FALSE		; UART: AUTO-DETECT DUAL UART
-UARTNABU	.EQU	FALSE		; UART: AUTO-DETECT NABU UART
 ;
 ASCIENABLE	.EQU	TRUE		; ASCI: ENABLE Z180 ASCI SERIAL DRIVER (ASCI.ASM)
 ASCIINTS	.EQU	TRUE		; ASCI: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
diff --git a/Source/HBIOS/cfg_nabu.asm b/Source/HBIOS/cfg_nabu.asm
index 3831d4e6..99198cce 100644
--- a/Source/HBIOS/cfg_nabu.asm
+++ b/Source/HBIOS/cfg_nabu.asm
@@ -139,7 +139,7 @@ UARTENABLE	.EQU	TRUE		; UART: ENABLE 8250/16550-LIKE SERIAL DRIVER (UART.ASM)
 UARTOSC		.EQU	1843200		; UART: OSC FREQUENCY IN MHZ
 UARTINTS	.EQU	FALSE		; UART: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
 UARTCFG		.EQU	DEFSERCFG | SER_RTS	; UART: LINE CONFIG FOR UART PORTS
-UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA/DUO ONBOARD UART
+UARTSBC		.EQU	TRUE		; UART: AUTO-DETECT SBC/ZETA/DUO/NABU ONBOARD UART
 UARTSBCFORCE	.EQU	FALSE		; UART: FORCE DETECTION OF SBC UART (FOR SIMH)
 UARTAUX		.EQU	FALSE		; UART: AUTO-DETECT AUX UART
 UARTCAS		.EQU	FALSE		; UART: AUTO-DETECT ECB CASSETTE UART
@@ -147,7 +147,6 @@ UARTMFP		.EQU	FALSE		; UART: AUTO-DETECT MF/PIC UART
 UART4		.EQU	FALSE		; UART: AUTO-DETECT 4UART UART
 UARTRC		.EQU	FALSE		; UART: AUTO-DETECT RC UART
 UARTDUAL	.EQU	FALSE		; UART: AUTO-DETECT DUAL UART
-UARTNABU	.EQU	TRUE		; UART: AUTO-DETECT NABU UART
 ;
 ASCIENABLE	.EQU	FALSE		; ASCI: ENABLE Z180 ASCI SERIAL DRIVER (ASCI.ASM)
 ;
diff --git a/Source/HBIOS/cfg_rcz180.asm b/Source/HBIOS/cfg_rcz180.asm
index a8c1e846..d1f2da99 100644
--- a/Source/HBIOS/cfg_rcz180.asm
+++ b/Source/HBIOS/cfg_rcz180.asm
@@ -145,7 +145,7 @@ UARTENABLE	.EQU	TRUE		; UART: ENABLE 8250/16550-LIKE SERIAL DRIVER (UART.ASM)
 UARTOSC		.EQU	1843200		; UART: OSC FREQUENCY IN MHZ
 UARTINTS	.EQU	FALSE		; UART: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
 UARTCFG		.EQU	DEFSERCFG | SER_RTS	; UART: LINE CONFIG FOR UART PORTS
-UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA/DUO ONBOARD UART
+UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA/DUO/NABU ONBOARD UART
 UARTSBCFORCE	.EQU	FALSE		; UART: FORCE DETECTION OF SBC UART (FOR SIMH)
 UARTAUX		.EQU	FALSE		; UART: AUTO-DETECT AUX UART
 UARTCAS		.EQU	FALSE		; UART: AUTO-DETECT ECB CASSETTE UART
@@ -153,7 +153,6 @@ UARTMFP		.EQU	FALSE		; UART: AUTO-DETECT MF/PIC UART
 UART4		.EQU	FALSE		; UART: AUTO-DETECT 4UART UART
 UARTRC		.EQU	TRUE		; UART: AUTO-DETECT RC UART
 UARTDUAL	.EQU	FALSE		; UART: AUTO-DETECT DUAL UART
-UARTNABU	.EQU	FALSE		; UART: AUTO-DETECT NABU UART
 ;
 ASCIENABLE	.EQU	TRUE		; ASCI: ENABLE Z180 ASCI SERIAL DRIVER (ASCI.ASM)
 ASCIINTS	.EQU	TRUE		; ASCI: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
diff --git a/Source/HBIOS/cfg_rcz280.asm b/Source/HBIOS/cfg_rcz280.asm
index 46edeaaf..f97f7033 100644
--- a/Source/HBIOS/cfg_rcz280.asm
+++ b/Source/HBIOS/cfg_rcz280.asm
@@ -139,7 +139,7 @@ UARTENABLE	.EQU	TRUE		; UART: ENABLE 8250/16550-LIKE SERIAL DRIVER (UART.ASM)
 UARTOSC		.EQU	1843200		; UART: OSC FREQUENCY IN MHZ
 UARTINTS	.EQU	FALSE		; UART: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
 UARTCFG		.EQU	DEFSERCFG | SER_RTS	; UART: LINE CONFIG FOR UART PORTS
-UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA/DUO ONBOARD UART
+UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA/DUO/NABU ONBOARD UART
 UARTSBCFORCE	.EQU	FALSE		; UART: FORCE DETECTION OF SBC UART (FOR SIMH)
 UARTAUX		.EQU	FALSE		; UART: AUTO-DETECT AUX UART
 UARTCAS		.EQU	FALSE		; UART: AUTO-DETECT ECB CASSETTE UART
@@ -147,7 +147,6 @@ UARTMFP		.EQU	FALSE		; UART: AUTO-DETECT MF/PIC UART
 UART4		.EQU	FALSE		; UART: AUTO-DETECT 4UART UART
 UARTRC		.EQU	TRUE		; UART: AUTO-DETECT RC UART
 UARTDUAL	.EQU	FALSE		; UART: AUTO-DETECT DUAL UART
-UARTNABU	.EQU	FALSE		; UART: AUTO-DETECT NABU UART
 ;
 ASCIENABLE	.EQU	FALSE		; ASCI: ENABLE Z180 ASCI SERIAL DRIVER (ASCI.ASM)
 ;
diff --git a/Source/HBIOS/cfg_rcz80.asm b/Source/HBIOS/cfg_rcz80.asm
index 66f815e5..7224ff1d 100644
--- a/Source/HBIOS/cfg_rcz80.asm
+++ b/Source/HBIOS/cfg_rcz80.asm
@@ -139,7 +139,7 @@ UARTENABLE	.EQU	TRUE		; UART: ENABLE 8250/16550-LIKE SERIAL DRIVER (UART.ASM)
 UARTOSC		.EQU	1843200		; UART: OSC FREQUENCY IN MHZ
 UARTINTS	.EQU	FALSE		; UART: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
 UARTCFG		.EQU	DEFSERCFG | SER_RTS	; UART: LINE CONFIG FOR UART PORTS
-UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA/DUO ONBOARD UART
+UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA/DUO/NABU ONBOARD UART
 UARTSBCFORCE	.EQU	FALSE		; UART: FORCE DETECTION OF SBC UART (FOR SIMH)
 UARTAUX		.EQU	FALSE		; UART: AUTO-DETECT AUX UART
 UARTCAS		.EQU	FALSE		; UART: AUTO-DETECT ECB CASSETTE UART
@@ -147,7 +147,6 @@ UARTMFP		.EQU	FALSE		; UART: AUTO-DETECT MF/PIC UART
 UART4		.EQU	FALSE		; UART: AUTO-DETECT 4UART UART
 UARTRC		.EQU	TRUE		; UART: AUTO-DETECT RC UART
 UARTDUAL	.EQU	FALSE		; UART: AUTO-DETECT DUAL UART
-UARTNABU	.EQU	FALSE		; UART: AUTO-DETECT NABU UART
 ;
 ASCIENABLE	.EQU	FALSE		; ASCI: ENABLE Z180 ASCI SERIAL DRIVER (ASCI.ASM)
 ;
diff --git a/Source/HBIOS/cfg_rph.asm b/Source/HBIOS/cfg_rph.asm
index 6f4af843..fbf1ebbf 100644
--- a/Source/HBIOS/cfg_rph.asm
+++ b/Source/HBIOS/cfg_rph.asm
@@ -133,7 +133,7 @@ UARTOSC		.EQU	1843200		; UART: OSC FREQUENCY IN MHZ
 UARTINTS	.EQU	FALSE		; UART: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
 UARTCFG		.EQU	DEFSERCFG	; UART: LINE CONFIG FOR UART PORTS
 UARTCASSPD	.EQU	SER_300_8N1	; UART: ECB CASSETTE UART DEFAULT SPEED
-UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA/DUO ONBOARD UART
+UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA/DUO/NABU ONBOARD UART
 UARTSBCFORCE	.EQU	FALSE		; UART: FORCE DETECTION OF SBC UART (FOR SIMH)
 UARTAUX		.EQU	FALSE		; UART: AUTO-DETECT AUX UART
 UARTCAS		.EQU	FALSE		; UART: AUTO-DETECT ECB CASSETTE UART
@@ -141,7 +141,6 @@ UARTMFP		.EQU	FALSE		; UART: AUTO-DETECT MF/PIC UART
 UART4		.EQU	FALSE		; UART: AUTO-DETECT 4UART UART
 UARTRC		.EQU	FALSE		; UART: AUTO-DETECT RC UART
 UARTDUAL	.EQU	FALSE		; UART: AUTO-DETECT DUAL UART
-UARTNABU	.EQU	FALSE		; UART: AUTO-DETECT NABU UART
 ;
 ASCIENABLE	.EQU	TRUE		; ASCI: ENABLE Z180 ASCI SERIAL DRIVER (ASCI.ASM)
 ASCIINTS	.EQU	TRUE		; ASCI: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
diff --git a/Source/HBIOS/cfg_s100.asm b/Source/HBIOS/cfg_s100.asm
index ce82688d..70800cf8 100644
--- a/Source/HBIOS/cfg_s100.asm
+++ b/Source/HBIOS/cfg_s100.asm
@@ -139,7 +139,7 @@ UARTENABLE	.EQU	FALSE		; UART: ENABLE 8250/16550-LIKE SERIAL DRIVER (UART.ASM)
 UARTOSC		.EQU	1843200		; UART: OSC FREQUENCY IN MHZ
 UARTINTS	.EQU	FALSE		; UART: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
 UARTCFG		.EQU	DEFSERCFG | SER_RTS	; UART: LINE CONFIG FOR UART PORTS
-UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA/DUO ONBOARD UART
+UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA/DUO/NABU ONBOARD UART
 UARTSBCFORCE	.EQU	FALSE		; UART: FORCE DETECTION OF SBC UART (FOR SIMH)
 UARTAUX		.EQU	FALSE		; UART: AUTO-DETECT AUX UART
 UARTCAS		.EQU	FALSE		; UART: AUTO-DETECT ECB CASSETTE UART
@@ -147,7 +147,6 @@ UARTMFP		.EQU	FALSE		; UART: AUTO-DETECT MF/PIC UART
 UART4		.EQU	FALSE		; UART: AUTO-DETECT 4UART UART
 UARTRC		.EQU	TRUE		; UART: AUTO-DETECT RC UART
 UARTDUAL	.EQU	FALSE		; UART: AUTO-DETECT DUAL UART
-UARTNABU	.EQU	FALSE		; UART: AUTO-DETECT NABU UART
 ;
 ASCIENABLE	.EQU	TRUE		; ASCI: ENABLE Z180 ASCI SERIAL DRIVER (ASCI.ASM)
 ASCIINTS	.EQU	TRUE		; ASCI: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
diff --git a/Source/HBIOS/cfg_sbc.asm b/Source/HBIOS/cfg_sbc.asm
index e0d85495..76cd046b 100644
--- a/Source/HBIOS/cfg_sbc.asm
+++ b/Source/HBIOS/cfg_sbc.asm
@@ -128,7 +128,7 @@ UARTOSC		.EQU	1843200		; UART: OSC FREQUENCY IN MHZ
 UARTINTS	.EQU	FALSE		; UART: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
 UARTCFG		.EQU	DEFSERCFG	; UART: LINE CONFIG FOR UART PORTS
 UARTCASSPD	.EQU	SER_300_8N1	; UART: ECB CASSETTE UART DEFAULT SPEED
-UARTSBC		.EQU	TRUE		; UART: AUTO-DETECT SBC/ZETA/DUO ONBOARD UART
+UARTSBC		.EQU	TRUE		; UART: AUTO-DETECT SBC/ZETA/DUO/NABU ONBOARD UART
 UARTSBCFORCE	.EQU	FALSE		; UART: FORCE DETECTION OF SBC UART (FOR SIMH)
 UARTAUX		.EQU	FALSE		; UART: AUTO-DETECT AUX UART
 UARTCAS		.EQU	TRUE		; UART: AUTO-DETECT ECB CASSETTE UART
@@ -136,7 +136,6 @@ UARTMFP		.EQU	TRUE		; UART: AUTO-DETECT MF/PIC UART
 UART4		.EQU	TRUE		; UART: AUTO-DETECT 4UART UART
 UARTRC		.EQU	FALSE		; UART: AUTO-DETECT RC UART
 UARTDUAL	.EQU	FALSE		; UART: AUTO-DETECT DUAL UART
-UARTNABU	.EQU	FALSE		; UART: AUTO-DETECT NABU UART
 ;
 ASCIENABLE	.EQU	FALSE		; ASCI: ENABLE Z180 ASCI SERIAL DRIVER (ASCI.ASM)
 ;
diff --git a/Source/HBIOS/cfg_scz180.asm b/Source/HBIOS/cfg_scz180.asm
index e91836c3..52849489 100644
--- a/Source/HBIOS/cfg_scz180.asm
+++ b/Source/HBIOS/cfg_scz180.asm
@@ -139,7 +139,7 @@ UARTENABLE	.EQU	TRUE		; UART: ENABLE 8250/16550-LIKE SERIAL DRIVER (UART.ASM)
 UARTOSC		.EQU	1843200		; UART: OSC FREQUENCY IN MHZ
 UARTINTS	.EQU	FALSE		; UART: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
 UARTCFG		.EQU	DEFSERCFG | SER_RTS	; UART: LINE CONFIG FOR UART PORTS
-UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA/DUO ONBOARD UART
+UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA/DUO/NABU ONBOARD UART
 UARTAUX		.EQU	FALSE		; UART: AUTO-DETECT AUX UART
 UARTSBCFORCE	.EQU	FALSE		; UART: FORCE DETECTION OF SBC UART (FOR SIMH)
 UARTCAS		.EQU	FALSE		; UART: AUTO-DETECT ECB CASSETTE UART
@@ -147,7 +147,6 @@ UARTMFP		.EQU	FALSE		; UART: AUTO-DETECT MF/PIC UART
 UART4		.EQU	FALSE		; UART: AUTO-DETECT 4UART UART
 UARTRC		.EQU	TRUE		; UART: AUTO-DETECT RC UART
 UARTDUAL	.EQU	FALSE		; UART: AUTO-DETECT DUAL UART
-UARTNABU	.EQU	FALSE		; UART: AUTO-DETECT NABU UART
 ;
 ASCIENABLE	.EQU	TRUE		; ASCI: ENABLE Z180 ASCI SERIAL DRIVER (ASCI.ASM)
 ASCIINTS	.EQU	TRUE		; ASCI: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
diff --git a/Source/HBIOS/cfg_z80retro.asm b/Source/HBIOS/cfg_z80retro.asm
index d087f5cc..e95c80ae 100644
--- a/Source/HBIOS/cfg_z80retro.asm
+++ b/Source/HBIOS/cfg_z80retro.asm
@@ -126,7 +126,7 @@ UARTOSC		.EQU	1843200		; UART: OSC FREQUENCY IN MHZ
 UARTINTS	.EQU	FALSE		; UART: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
 UARTCFG		.EQU	DEFSERCFG	; UART: LINE CONFIG FOR UART PORTS
 UARTCASSPD	.EQU	SER_300_8N1	; UART: ECB CASSETTE UART DEFAULT SPEED
-UARTSBC		.EQU	TRUE		; UART: AUTO-DETECT SBC/ZETA/DUO ONBOARD UART
+UARTSBC		.EQU	TRUE		; UART: AUTO-DETECT SBC/ZETA/DUO/NABU ONBOARD UART
 UARTAUX		.EQU	FALSE		; UART: AUTO-DETECT AUX UART
 UARTSBCFORCE	.EQU	FALSE		; UART: FORCE DETECTION OF SBC UART (FOR SIMH)
 UARTCAS		.EQU	FALSE		; UART: AUTO-DETECT ECB CASSETTE UART
@@ -134,7 +134,6 @@ UARTMFP		.EQU	FALSE		; UART: AUTO-DETECT MF/PIC UART
 UART4		.EQU	FALSE		; UART: AUTO-DETECT 4UART UART
 UARTRC		.EQU	FALSE		; UART: AUTO-DETECT RC UART
 UARTDUAL	.EQU	FALSE		; UART: AUTO-DETECT DUAL UART
-UARTNABU	.EQU	FALSE		; UART: AUTO-DETECT NABU UART
 ;
 ASCIENABLE	.EQU	FALSE		; ASCI: ENABLE Z180 ASCI SERIAL DRIVER (ASCI.ASM)
 ;
diff --git a/Source/HBIOS/cfg_zeta.asm b/Source/HBIOS/cfg_zeta.asm
index f0ed536c..0b3c409f 100644
--- a/Source/HBIOS/cfg_zeta.asm
+++ b/Source/HBIOS/cfg_zeta.asm
@@ -115,7 +115,7 @@ UARTOSC		.EQU	1843200		; UART: OSC FREQUENCY IN MHZ
 UARTINTS	.EQU	FALSE		; UART: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
 UARTCFG		.EQU	DEFSERCFG	; UART: LINE CONFIG FOR UART PORTS
 UARTCASSPD	.EQU	SER_300_8N1	; UART: ECB CASSETTE UART DEFAULT SPEED
-UARTSBC		.EQU	TRUE		; UART: AUTO-DETECT SBC/ZETA ONBOARD UART
+UARTSBC		.EQU	TRUE		; UART: AUTO-DETECT SBC/ZETA/DUO/NABU ONBOARD UART
 UARTSBCFORCE	.EQU	FALSE		; UART: FORCE DETECTION OF SBC UART (FOR SIMH)
 UARTAUX		.EQU	FALSE		; UART: AUTO-DETECT AUX UART
 UARTCAS		.EQU	FALSE		; UART: AUTO-DETECT ECB CASSETTE UART
@@ -123,7 +123,6 @@ UARTMFP		.EQU	FALSE		; UART: AUTO-DETECT MF/PIC UART
 UART4		.EQU	FALSE		; UART: AUTO-DETECT 4UART UART
 UARTRC		.EQU	FALSE		; UART: AUTO-DETECT RC UART
 UARTDUAL	.EQU	FALSE		; UART: AUTO-DETECT DUAL UART
-UARTNABU	.EQU	FALSE		; UART: AUTO-DETECT NABU UART
 ;
 ASCIENABLE	.EQU	FALSE		; ASCI: ENABLE Z180 ASCI SERIAL DRIVER (ASCI.ASM)
 ;
diff --git a/Source/HBIOS/cfg_zeta2.asm b/Source/HBIOS/cfg_zeta2.asm
index 0c33dfa0..7e3c6f10 100644
--- a/Source/HBIOS/cfg_zeta2.asm
+++ b/Source/HBIOS/cfg_zeta2.asm
@@ -126,7 +126,7 @@ UARTOSC		.EQU	1843200		; UART: OSC FREQUENCY IN MHZ
 UARTINTS	.EQU	FALSE		; UART: INCLUDE INTERRUPT SUPPORT UNDER IM1/2/3
 UARTCFG		.EQU	DEFSERCFG	; UART: LINE CONFIG FOR UART PORTS
 UARTCASSPD	.EQU	SER_300_8N1	; UART: ECB CASSETTE UART DEFAULT SPEED
-UARTSBC		.EQU	TRUE		; UART: AUTO-DETECT SBC/ZETA/DUO ONBOARD UART
+UARTSBC		.EQU	TRUE		; UART: AUTO-DETECT SBC/ZETA/DUO/NABU ONBOARD UART
 UARTSBCFORCE	.EQU	FALSE		; UART: FORCE DETECTION OF SBC UART (FOR SIMH)
 UARTAUX		.EQU	FALSE		; UART: AUTO-DETECT AUX UART
 UARTCAS		.EQU	FALSE		; UART: AUTO-DETECT ECB CASSETTE UART
@@ -134,7 +134,6 @@ UARTMFP		.EQU	FALSE		; UART: AUTO-DETECT MF/PIC UART
 UART4		.EQU	FALSE		; UART: AUTO-DETECT 4UART UART
 UARTRC		.EQU	FALSE		; UART: AUTO-DETECT RC UART
 UARTDUAL	.EQU	FALSE		; UART: AUTO-DETECT DUAL UART
-UARTNABU	.EQU	FALSE		; UART: AUTO-DETECT NABU UART
 ;
 ASCIENABLE	.EQU	FALSE		; ASCI: ENABLE Z180 ASCI SERIAL DRIVER (ASCI.ASM)
 ;
diff --git a/Source/HBIOS/hbios.asm b/Source/HBIOS/hbios.asm
index f348a336..8f340c68 100644
--- a/Source/HBIOS/hbios.asm
+++ b/Source/HBIOS/hbios.asm
@@ -2371,7 +2371,7 @@ HB_CPU3:
 #ENDIF
 ;
 ;--------------------------------------------------------------------------------------------------
-; SYSTEM TIME INITIALIZATION
+; SYSTEM TIMER INITIALIZATION
 ;--------------------------------------------------------------------------------------------------
 ;
 #IF (PLATFORM == PLT_SBC)
@@ -2707,6 +2707,34 @@ NXTMIO:	LD	A,(HL)
 NOT_REC_M2:
 ;
 	FPLEDS(DIAG_08)
+
+#IF (PLATFORM == PLT_NABU) & TRUE
+;
+	; GET CURRENT VALUE OF PSG ENABLE REGISTER
+	LD	A,7
+	OUT	(NABU_RSEL),A
+	NOP
+	IN	A,(NABU_RDAT)
+	LD	B,A
+;
+	; GET CURRENT VALUE OF PSG ENABLE REGISTER
+	LD	A,7
+	OUT	(NABU_RSEL),A
+	NOP
+	IN	A,(NABU_RDAT)
+	LD	C,A
+;
+	; DUMP IT
+	CALL	PC_ASTERISK
+	LD	A,B
+	CALL	PRTHEXBYTE
+	LD	A,C
+	CALL	PRTHEXBYTE
+	CALL	PC_ASTERISK
+;
+#ENDIF
+
+
 ;
 ;--------------------------------------------------------------------------------------------------
 ; IO PORT SCAN
@@ -3061,6 +3089,7 @@ HB_CKBNKSIZ	.EQU	$-HB_CKBNK	; SIZE OF ROUTINE
 HB_ROMCKZ:
 ;
   #ENDIF
+;
 #ENDIF
 ;
 ;--------------------------------------------------------------------------------------------------
diff --git a/Source/HBIOS/nabu.asm b/Source/HBIOS/nabu.asm
index 7a395f60..ec3a1cf7 100644
--- a/Source/HBIOS/nabu.asm
+++ b/Source/HBIOS/nabu.asm
@@ -51,10 +51,17 @@ NABU_PREINIT:
 ;
 	CALL	NABU_SETPSG	
 ;
-	; ADD TO INTERRUPT CHAIN
-	LD	HL,NABU_STAT
-	CALL	HB_ADDIM1		; ADD TO IM1 CALL LIST
-	RET
+;#IF (INTMODE == 1)
+;	; ADD TO INTERRUPT CHAIN
+;	LD	HL,NABU_STAT
+;	CALL	HB_ADDIM1		; ADD TO IM1 CALL LIST
+;#ENDIF
+;
+;#IF (INTMODE == 2)
+;	LD	HL,NABU_STAT
+;	LD	(IVT(INT_NABUKB)),HL	; IVT INDEX
+;#ENDIF
+;	RET
 ;
 NABU_INIT:
 	CALL	NEWLINE			; FORMATTING
@@ -70,11 +77,15 @@ NABU_SETPSG:
 	LD	A,%01111111		; PORT B INPUT, PORT A OUPUT
 	OUT	(NABU_RDAT),A		; SET IT
 ;
-;	; SET PORT A TO VALUE 0
-;	LD	A,14			; PSG R14 (PORT A DATA)
-;	OUT	(NABU_RSEL),A		; SELECT IT
-;	XOR	A			; VALUE 0
-;	OUT	(NABU_RDAT),A		; SET IT
+	; SET PORT A TO VALUE 0
+	LD	A,14			; PSG R14 (PORT A DATA)
+	OUT	(NABU_RSEL),A		; SELECT IT
+#IF (INTMODE > 0)
+	LD	A,%00100000		; ENABLE NABU KB INTS
+#ELSE
+	XOR	A
+#ENDIF
+	OUT	(NABU_RDAT),A		; SET IT
 ;
 	LD	A,15
 	OUT	(NABU_RSEL),A
@@ -84,10 +95,12 @@ NABU_SETPSG:
 ;  INTERRUPT ENTRY POINT
 ;
 NABU_STAT:
-	CALL	NABU_SETPSG
+;	CALL	NABU_SETPSG
 ;	XOR	A
 ;	OUT	(NABU_INT1CLR),A	; CLEAR THE INTERRUPT
 	LD	HL,(NABU_TICCNT)	; INCREMENT NABU TICK COUNTER
+	
+	
 	INC	HL			; ... IN HBIOS PROXY
 	LD	(NABU_TICCNT),HL
 ;	LD	A,(NABU_HBTICK)		; INCREMENT INTERNAL TICK CTR
diff --git a/Source/HBIOS/nabukb.asm b/Source/HBIOS/nabukb.asm
index 9bcaf745..5d949032 100644
--- a/Source/HBIOS/nabukb.asm
+++ b/Source/HBIOS/nabukb.asm
@@ -44,16 +44,35 @@
 ;	LD	A,04H
 ;	CALL	SUB12
 ;
-NABUKB_DAT	.EQU	$90
+NABUKB_IODAT	.EQU	$90		; KEYBOARD DATA (READ)
+NABUKB_IOSTAT	.EQU	$91		; STATUS (READ), CMD (WRITE)
 ;
 	DEVECHO	"NABUKB: IO="
-	DEVECHO	NABUKB_DAT
+	DEVECHO	NABUKB_IODAT
 	DEVECHO	"\n"
 ;
+; SETUP INTERRUPT HANDLING, IF ENABLED
+;
+NABUKB_PREINIT:
+#IF (INTMODE == 1)
+	; ADD TO INTERRUPT CHAIN
+	LD	HL,NABUKB_INT
+	CALL	HB_ADDIM1		; ADD TO IM1 CALL LIST
+#ENDIF
+;
+#IF (INTMODE == 2)
+	; INSTALL VECTOR
+	LD	HL,NABUKB_INT
+	LD	(IVT(INT_NABUKB)),HL	; IVT INDEX
+#ENDIF
+	RET
+;
+; INITIALZIZE THE KEYBOARD CONTROLLER.
+;
 NABUKB_INIT:
 	CALL	NEWLINE
 	PRTS("NABUKB: IO=0x$")
-	LD	A,NABUKB_DAT
+	LD	A,NABUKB_IODAT
 	CALL	PRTHEXBYTE
 ;
 	XOR	A
@@ -72,36 +91,82 @@ NABUKB_INIT:
 	XOR	A
 	RET
 ;
+#IF (INTMODE > 0)
+;
+; INTERRUPT HANDLER FOR NABU KEYBOARD.  HANDLES INTERRUPTS FOR EITHER
+; INT MODE 1 OR INT MODE 2.  THE KEYBOARD BUFFER IS JUST A SINGLE CHAR
+; AT THIS POINT.  NEW CHARACTERS ARRIVING WHEN THE BUFFER IS FULL WILL
+; BE DISCARDED.
+;
+NABUKB_INT:
+	IN	A,(NABUKB_IOSTAT)	; GET KBD STATUS
+	AND	$02			; CHECK DATA RDY BIT
+	RET	Z			; ABORT W/ Z (INT NOT HANDLED)
+;
+	;CALL	PC_LT			; *DEBUG*
+	IN	A,(NABUKB_IODAT)	; GET THE KEY
+	LD	E,A			; STASH IN REG E
+	;CALL	PRTHEXBYTE		; *DEBUG*
+	;CALL	PC_GT			; *DEBUG*
+;
+	LD	A,(NABUKB_KSTAT)	; GET KEY BUFFER STAT
+	OR	A			; SET FLAGS
+	RET	NZ			; BUFFER FULL, BAIL OUT W/ NZ (INT HANDLED), KEY DISCARDED
+;
+	LD	A,E			; RECOVER THE KEY CODE
+	CALL	NABUKB_XB		; TRANSLATE AND BUFFER KEY
+	OR	$FF			; SIGNAL INT HANDLED
+	RET				; DONE
+;
+#ENDIF
+;
+; NORMAL HBIOS CHAR INPUT STATUS.  IF INTERRUPTS ARE NOT ACTIVE, THEN
+; KEYBOARD POLLING IS IMPLEMENTED HERE.
+;
 NABUKB_STAT:
 	LD	A,(NABUKB_KSTAT)	; GET KEY WAITING STATUS
 	OR	A			; SET FLAGS
+#IF (INTMODE > 0)
+	JR	Z,NABUKB_STATX		; BAIL OUT W/ Z (NO KEY)
+	RET				; KEY WAITING, ALL SET
+#ELSE
 	RET	NZ			; KEY WAITING, ALL SET
-	IN	A,(NABUKB_DAT+1)	; GET BKD STATUS
+	IN	A,(NABUKB_IOSTAT)	; GET KBD STATUS
 	AND	$02			; CHECK DATA RDY BIT
-	JR	Z,NABUKB_STATX		; BAIL OUT IF NOT
-	IN	A,(NABUKB_DAT)		; GET THE KEY
+	JR	Z,NABUKB_STATX		; BAIL OUT W/ Z (NO KEY)
+	IN	A,(NABUKB_IODAT)	; GET THE KEY
+	CALL	NABUKB_XB		; TRANSLATE AND BUFFER KEY
+	LD	A,(NABUKB_KSTAT)	; GET NEW KEY WAITING STATUS
+	OR	A			; SET FLAGS
+	RET				; DONE
+#ENDIF
+;
+NABUKB_STATX:
+	XOR	A			; SIGNAL NO CHAR READY
+	JP	CIO_IDLE		; RETURN VIA IDLE PROCESSOR
+;
+; ROUTINE TO TRANSLATE AND BUFFER INCOMING NABU KEYBOARD KEYCODES
+;
+NABUKB_XB:
 	BIT	7,A			; HIGH BIT IS SPECIAL CHAR
-	JR	Z,NABUKB_STAT2		; IF NORMAL CHAR, BUFFER IT
+	JR	Z,NABUKB_XB2		; IF NORMAL CHAR, BUFFER IT
 	CP	$90			; START OF ERR CODES
-	JR	C,NABUKB_STAT1		; NOT ERR CODE, CONTINUE
+	JR	C,NABUKB_XB1		; NOT ERR CODE, CONTINUE
 	CP	$A0			; END OF ERR CODES
-	JR	NC,NABUKB_STAT1		; NOT ERR CODE, CONTINUE
-	JR	NABUKB_STATX		; IS ERR CODE, IGNORE IT
-NABUKB_STAT1:
+	JR	NC,NABUKB_XB1		; NOT ERR CODE, CONTINUE
+	RET				; DISCARD ERR CODE AND RETURN
+NABUKB_XB1:
 	CP	$E0			; SPECIAL CHARACTER?
-	JR	C,NABUKB_STAT2		; IF NOT, SKIP XLAT, BUFFER KEY
+	JR	C,NABUKB_XB2		; IF NOT, SKIP XLAT, BUFFER KEY
 	CALL	NABUKB_XLAT		; IF SO, TRANSLATE IT
-	JR	C,NABUKB_STATX		; CF INDICATES INVALID
-NABUKB_STAT2:
+	RET	C			; CF INDICATES INVALID, DISCARD AND RETURN
+NABUKB_XB2:
 	LD	(NABUKB_KEY),A		; BUFFER IT
 	LD	A,1			; SIGNAL KEY WAITING
 	LD	(NABUKB_KSTAT),A	; SAVE IT
-	OR	A			; SET FLAGS
 	RET				; DONE
 ;
-NABUKB_STATX:
-	XOR	A			; SIGNAL NO CHAR READY
-	JP	CIO_IDLE		; RETURN VIA IDLE PROCESSOR
+; ROUTINE TO TRANSLATE SPECIAL NABU KEYBOARD KEY CODES
 ;
 NABUKB_XLAT:
 	; NABU KEYBOARD USES $E0-$FF FOR SPECIAL KEYS
@@ -121,10 +186,15 @@ NABUKB_XLAT1:
 	SCF				; SIGNAL INVALID
 	RET				; AND DONE
 ;
+; FLUSH KEYBOARD BUFFER
+;
 NABUKB_FLUSH:
 	XOR	A
+	LD	(NABUKB_KSTAT),A
 	RET
 ;
+; WAIT FOR A KEY TO BE READY AND RETURN IT.
+;
 NABUKB_READ:
 	CALL	NABUKB_STAT		; CHECK FOR KEY READY
 	JR	Z,NABUKB_READ		; LOOP TIL ONE IS READY
@@ -136,8 +206,10 @@ NABUKB_READ:
 	LD	(NABUKB_KSTAT),A	; CLEAR KEY WAITING STATUS
 	RET				; AND RETURN
 ;
+; HELPER ROUTINE TO WRITE 
+;
 NABUKB_PUT:
-	OUT	(NABUKB_DAT+1),A
+	OUT	(NABUKB_IOSTAT),A
 	NOP
 	NOP
 	NOP
@@ -155,36 +227,37 @@ NABUKB_KEY	.DB	0	; KEY BUFFER
 ; NABU KEY CODE $E0 AND HANDLES $20 POSSIBLE VALUES ($E0-$FF)
 ; THE SPECIAL KEYS SEND A SPECIFIC KEYCODE TO INDICATE DOWN (KEY
 ; PRESSED) AND UP (KEY RELEASED).  WE WILL ARBITRARILY CHOOSE TO
-; RESPOND TO KEY RELEASED.
+; RESPOND TO KEY PRESSED.  a TRANSLATION VALUE OF $00 MEANS THAT THE
+; KEY CODE SHOULD BE DISCARDED.
 ;
 NABUKB_XTBL:
-	.DB	$00		; $E0, RIGHT ARROW (DN)
-	.DB	$00		; $E1, LEFT ARROW (DN)
-	.DB	$00		; $E2, UP ARROW (DN)
-	.DB	$00		; $E3, DOWN ARROW (DN)
-	.DB	$00		; $E4, PAGE RIGHT (DN)
-	.DB	$00		; $E5, PAGE LEFT (DN)
-	.DB	$00		; $E6, NO (DN)
-	.DB	$00		; $E7, YES (DN)
-	.DB	$00		; $E8, SYM (DN)
-	.DB	$00		; $E9, PAUSE (DN)
-	.DB	$00		; $EA, TV/NABU (DN)
+	.DB	$F9		; $E0, RIGHT ARROW (DN) -> RIGHT ARROW
+	.DB	$F8		; $E1, LEFT ARROW (DN) -> LEFT ARROW
+	.DB	$F6		; $E2, UP ARROW (DN) -> UP ARROW
+	.DB	$F7		; $E3, DOWN ARROW (DN) -> DOWN ARROW
+	.DB	$F5		; $E4, PAGE RIGHT (DN) -> PAGE DOWN
+	.DB	$F4		; $E5, PAGE LEFT (DN) -> PAGE UP
+	.DB	$F3		; $E6, NO (DN) -> END
+	.DB	$F2		; $E7, YES (DN) -> HOME
+	.DB	$EE		; $E8, SYM (DN) -> SYSRQ
+	.DB	$EF		; $E9, PAUSE (DN) -> PAUSE
+	.DB	$00		; $EA, TV/NABU (DN) -> APP
 	.DB	$00		; $EB, N/A
 	.DB	$00		; $EC, N/A
 	.DB	$00		; $ED, N/A
 	.DB	$00		; $EE, N/A
 	.DB	$00		; $EF, N/A
-	.DB	$F9		; $F0, RIGHT ARROW (UP) -> RIGHT ARROW
-	.DB	$F8		; $F1, LEFT ARROW (UP) -> LEFT ARROW
-	.DB	$F6		; $F2, UP ARROW (UP) -> UP ARROW
-	.DB	$F7		; $F3, DOWN ARROW (UP) -> DOWN ARROW
-	.DB	$F5		; $F4, PAGE RIGHT (UP) -> PAGE DOWN
-	.DB	$F4		; $F5, PAGE LEFT (UP) -> PAGE UP
-	.DB	$F3		; $F6, NO (UP) -> END
-	.DB	$F2		; $F7, YES (UP) -> HOME
-	.DB	$EC		; $F8, SYM (UP) -> SYSRQ
-	.DB	$EE		; $F9, PAUSE (UP) -> PAUSE
-	.DB	$EF		; $FA, TV/NABU (UP) -> APP
+	.DB	$00		; $F0, RIGHT ARROW (UP)
+	.DB	$00		; $F1, LEFT ARROW (UP)
+	.DB	$00		; $F2, UP ARROW (UP)
+	.DB	$00		; $F3, DOWN ARROW (UP)
+	.DB	$00		; $F4, PAGE RIGHT (UP)
+	.DB	$00		; $F5, PAGE LEFT (UP)
+	.DB	$00		; $F6, NO (UP)
+	.DB	$00		; $F7, YES (UP)
+	.DB	$00		; $F8, SYM (UP)
+	.DB	$00		; $F9, PAUSE (UP)
+	.DB	$00		; $FA, TV/NABU (UP)
 	.DB	$00		; $FB, N/A
 	.DB	$00		; $FC, N/A
 	.DB	$00		; $FD, N/A
diff --git a/Source/HBIOS/std.asm b/Source/HBIOS/std.asm
index 2697541d..6ee025ce 100644
--- a/Source/HBIOS/std.asm
+++ b/Source/HBIOS/std.asm
@@ -1049,7 +1049,22 @@ INT_PIO1B	.EQU	12	; ZILOG PIO 1, CHANNEL B
 
   #ENDIF
 
-  #IF ((PLATFORM != PLT_MBC) & (PLATFORM != PLT_DUO))
+  #IF (PLATFORM == PLT_NABU)
+;
+; NABU Z80 IM2 INTERRUPTS
+;
+INT_HCAARCV	.EQU	0	; UART 0
+INT_HCAASND	.EQU	1	; UART 1 ?????
+INT_NABUKB	.EQU	2	; ZILOG CTC 0, CHANNEL A
+INT_VDP		.EQU	3	; ZILOG CTC 0, CHANNEL B
+INT_OPTCRD0	.EQU	4	; ZILOG CTC 0, CHANNEL C
+INT_OPTCRD1	.EQU	5	; ZILOG CTC 0, CHANNEL D
+INT_OPTCRD2	.EQU	6	; ZILOG SIO 0, CHANNEL A & B
+INT_OPTCRD3	.EQU	7	; ZILOG SIO 1, CHANNEL A & B
+
+  #ENDIF
+
+  #IF ((PLATFORM != PLT_MBC) & (PLATFORM != PLT_DUO) & (PLATFORM != PLT_NABU))
 
 ; GENERIC Z80 M2 INTERRUPTS
 
diff --git a/Source/HBIOS/tms.asm b/Source/HBIOS/tms.asm
index eaed9dfe..0fd7fac3 100644
--- a/Source/HBIOS/tms.asm
+++ b/Source/HBIOS/tms.asm
@@ -179,6 +179,9 @@ NABUKBENABLE	.SET	TRUE		; INCLUDE NABU KEYBOARD SUPPORT
 ;======================================================================
 ;
 TMS_PREINIT:
+#IF (NABUKBENABLE == TRUE)
+	CALL NABUKB_PREINIT
+#ENDIF
 	; DISABLE INTERRUPT GENERATION
 	LD	A, (TMS_INITVDU_REG_1)
         RES	TMSINTEN, A             ; RESET INTERRUPT ENABLE BIT
diff --git a/Source/HBIOS/uart.asm b/Source/HBIOS/uart.asm
index d012b33c..bedf4487 100644
--- a/Source/HBIOS/uart.asm
+++ b/Source/HBIOS/uart.asm
@@ -57,7 +57,14 @@ UART_CTSBAD		.EQU	4	; CTS STALL DETECTED
 #IF (PLATFORM == PLT_DUO)
 UARTSBASE		.EQU	$58
 UARTDBASE		.EQU	$70
-#ELSE
+#ENDIF
+;
+#IF (PLATFORM == PLT_NABU)
+UARTSBASE		.EQU	$48
+UARTDBASE		.EQU	$80
+#ENDIF
+;
+#IF ((PLATFORM != PLT_DUO) & (PLATFORM != PLT_NABU))
 UARTSBASE		.EQU	$68
 UARTDBASE		.EQU	$80
 #ENDIF
@@ -67,7 +74,6 @@ UARTCBASE		.EQU	$80
 UARTMBASE		.EQU	$18
 UART4BASE		.EQU	$C0
 UARTRBASE		.EQU	$A0
-UARTNBASE		.EQU	$48
 ;
 #IF (UARTINTS)
 ;
@@ -79,7 +85,6 @@ UART1_IVT	.EQU	IVT(INT_UART1)
   #ENDIF
 ;
 #ENDIF
-
 ;
 #DEFINE	UART_INP(RID)	CALL UART_INP_IMP \ .DB RID
 #DEFINE	UART_OUTP(RID)	CALL UART_OUTP_IMP \ .DB RID
@@ -1185,18 +1190,6 @@ UART_CFG_MFP:
 	DEVECHO	"\n"
 ;
 #ENDIF
-#IF (UARTNABU)
-	.DB	0				; DEVICE NUMBER (UPDATED DURING INIT)
-	.DB	0				; UART TYPE
-	.DB	UARTNBASE			; IO PORT BASE (RBR, THR)
-	.DB	UARTNBASE + UART_LSR		; LINE STATUS PORT (LSR)
-	.DW	UARTCFG				; LINE CONFIGURATION
-	.DW	0				; SHOULD NEVER NEED INT HANDLER
-;
-	DEVECHO	"UART: MODE=NABU, IO="
-	DEVECHO	UARTNBASE
-	DEVECHO	"\n"
-#ENDIF
 ;
 UART_CNT	.EQU	($ - UART_CFG) / 8
 ;
diff --git a/Source/ver.inc b/Source/ver.inc
index d18d8523..9971ed7e 100644
--- a/Source/ver.inc
+++ b/Source/ver.inc
@@ -2,7 +2,7 @@
 #DEFINE	RMN	5
 #DEFINE	RUP	0
 #DEFINE	RTP	0
-#DEFINE BIOSVER	"3.5.0-dev.36"
+#DEFINE BIOSVER	"3.5.0-dev.37"
 #define rmj	RMJ
 #define rmn	RMN
 #define rup	RUP
diff --git a/Source/ver.lib b/Source/ver.lib
index 358b95ae..4feb605b 100644
--- a/Source/ver.lib
+++ b/Source/ver.lib
@@ -3,5 +3,5 @@ rmn	equ	5
 rup	equ	0
 rtp	equ	0
 biosver	macro
-	db	"3.5.0-dev.36"
+	db	"3.5.0-dev.37"
 	endm