diff --git a/Source/HBIOS/cfg_duo.asm b/Source/HBIOS/cfg_duo.asm
index 9669f344..cccb1f69 100644
--- a/Source/HBIOS/cfg_duo.asm
+++ b/Source/HBIOS/cfg_duo.asm
@@ -126,14 +126,13 @@ 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 ONBOARD UART
+UARTSBC		.EQU	TRUE		; UART: AUTO-DETECT SBC/ZETA/DUO ONBOARD UART
 UARTSBCFORCE	.EQU	FALSE		; UART: FORCE DETECTION OF SBC UART (FOR SIMH)
 UARTCAS		.EQU	FALSE		; UART: AUTO-DETECT ECB CASSETTE UART
 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
-UARTDUO		.EQU	TRUE		; UART: AUTO-DETECT DUODYNE 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 ec467a58..b4ac149a 100644
--- a/Source/HBIOS/cfg_dyno.asm
+++ b/Source/HBIOS/cfg_dyno.asm
@@ -129,14 +129,13 @@ 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 ONBOARD UART
+UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA/DUO ONBOARD UART
 UARTSBCFORCE	.EQU	FALSE		; UART: FORCE DETECTION OF SBC UART (FOR SIMH)
 UARTCAS		.EQU	FALSE		; UART: AUTO-DETECT ECB CASSETTE UART
 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
-UARTDUO		.EQU	FALSE		; UART: AUTO-DETECT DUODYNE 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_master.asm b/Source/HBIOS/cfg_master.asm
index f7c875a4..cec52d66 100644
--- a/Source/HBIOS/cfg_master.asm
+++ b/Source/HBIOS/cfg_master.asm
@@ -165,14 +165,13 @@ 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 ONBOARD UART
+UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA/DUO ONBOARD UART
 UARTSBCFORCE	.EQU	FALSE		; UART: FORCE DETECTION OF SBC UART (FOR SIMH)
 UARTCAS		.EQU	FALSE		; UART: AUTO-DETECT ECB CASSETTE UART
 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
-UARTDUO		.EQU	FALSE		; UART: AUTO-DETECT DUODYNE 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 282de56f..28cc5b54 100644
--- a/Source/HBIOS/cfg_mbc.asm
+++ b/Source/HBIOS/cfg_mbc.asm
@@ -123,14 +123,13 @@ 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 ONBOARD UART
 UARTSBCFORCE	.EQU	FALSE		; UART: FORCE DETECTION OF SBC UART (FOR SIMH)
 UARTCAS		.EQU	FALSE		; UART: AUTO-DETECT ECB CASSETTE UART
 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
-UARTDUO		.EQU	FALSE		; UART: AUTO-DETECT DUODYNE 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 865177f0..31b764cd 100644
--- a/Source/HBIOS/cfg_mk4.asm
+++ b/Source/HBIOS/cfg_mk4.asm
@@ -129,14 +129,13 @@ 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 ONBOARD UART
+UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA/DUO ONBOARD UART
 UARTSBCFORCE	.EQU	FALSE		; UART: FORCE DETECTION OF SBC UART (FOR SIMH)
 UARTCAS		.EQU	TRUE		; UART: AUTO-DETECT ECB CASSETTE UART
 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
-UARTDUO		.EQU	FALSE		; UART: AUTO-DETECT DUODYNE 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_n8.asm b/Source/HBIOS/cfg_n8.asm
index db721cb8..78c03f83 100644
--- a/Source/HBIOS/cfg_n8.asm
+++ b/Source/HBIOS/cfg_n8.asm
@@ -131,14 +131,13 @@ 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 ONBOARD UART
+UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA/DUO ONBOARD UART
 UARTSBCFORCE	.EQU	FALSE		; UART: FORCE DETECTION OF SBC UART (FOR SIMH)
 UARTCAS		.EQU	TRUE		; UART: AUTO-DETECT ECB CASSETTE UART
 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
-UARTDUO		.EQU	FALSE		; UART: AUTO-DETECT DUODYNE 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_rcz180.asm b/Source/HBIOS/cfg_rcz180.asm
index 951a6be8..e9331174 100644
--- a/Source/HBIOS/cfg_rcz180.asm
+++ b/Source/HBIOS/cfg_rcz180.asm
@@ -135,14 +135,13 @@ 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 ONBOARD UART
+UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA/DUO ONBOARD UART
 UARTSBCFORCE	.EQU	FALSE		; UART: FORCE DETECTION OF SBC UART (FOR SIMH)
 UARTCAS		.EQU	FALSE		; UART: AUTO-DETECT ECB CASSETTE UART
 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
-UARTDUO		.EQU	FALSE		; UART: AUTO-DETECT DUODYNE 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 b584eedd..32c737ed 100644
--- a/Source/HBIOS/cfg_rcz280.asm
+++ b/Source/HBIOS/cfg_rcz280.asm
@@ -129,14 +129,13 @@ 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 ONBOARD UART
+UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA/DUO ONBOARD UART
 UARTSBCFORCE	.EQU	FALSE		; UART: FORCE DETECTION OF SBC UART (FOR SIMH)
 UARTCAS		.EQU	FALSE		; UART: AUTO-DETECT ECB CASSETTE UART
 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
-UARTDUO		.EQU	FALSE		; UART: AUTO-DETECT DUODYNE 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 d058e7a1..78ccc76c 100644
--- a/Source/HBIOS/cfg_rcz80.asm
+++ b/Source/HBIOS/cfg_rcz80.asm
@@ -128,14 +128,13 @@ 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 ONBOARD UART
+UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA/DUO ONBOARD UART
 UARTSBCFORCE	.EQU	FALSE		; UART: FORCE DETECTION OF SBC UART (FOR SIMH)
 UARTCAS		.EQU	FALSE		; UART: AUTO-DETECT ECB CASSETTE UART
 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
-UARTDUO		.EQU	FALSE		; UART: AUTO-DETECT DUODYNE 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 5c55f198..7c01e095 100644
--- a/Source/HBIOS/cfg_rph.asm
+++ b/Source/HBIOS/cfg_rph.asm
@@ -129,14 +129,13 @@ 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 ONBOARD UART
+UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA/DUO ONBOARD UART
 UARTSBCFORCE	.EQU	FALSE		; UART: FORCE DETECTION OF SBC UART (FOR SIMH)
 UARTCAS		.EQU	FALSE		; UART: AUTO-DETECT ECB CASSETTE UART
 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
-UARTDUO		.EQU	FALSE		; UART: AUTO-DETECT DUODYNE 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 3d3abf37..0a4d7928 100644
--- a/Source/HBIOS/cfg_s100.asm
+++ b/Source/HBIOS/cfg_s100.asm
@@ -129,14 +129,13 @@ 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 ONBOARD UART
+UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA/DUO ONBOARD UART
 UARTSBCFORCE	.EQU	FALSE		; UART: FORCE DETECTION OF SBC UART (FOR SIMH)
 UARTCAS		.EQU	FALSE		; UART: AUTO-DETECT ECB CASSETTE UART
 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
-UARTDUO		.EQU	FALSE		; UART: AUTO-DETECT DUODYNE 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 729b4073..5bf1244f 100644
--- a/Source/HBIOS/cfg_sbc.asm
+++ b/Source/HBIOS/cfg_sbc.asm
@@ -123,14 +123,13 @@ 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 ONBOARD UART
 UARTSBCFORCE	.EQU	FALSE		; UART: FORCE DETECTION OF SBC UART (FOR SIMH)
 UARTCAS		.EQU	TRUE		; UART: AUTO-DETECT ECB CASSETTE UART
 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
-UARTDUO		.EQU	FALSE		; UART: AUTO-DETECT DUODYNE 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 efa75020..f3f5d5aa 100644
--- a/Source/HBIOS/cfg_scz180.asm
+++ b/Source/HBIOS/cfg_scz180.asm
@@ -129,14 +129,13 @@ 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 ONBOARD UART
+UARTSBC		.EQU	FALSE		; UART: AUTO-DETECT SBC/ZETA/DUO ONBOARD UART
 UARTSBCFORCE	.EQU	FALSE		; UART: FORCE DETECTION OF SBC UART (FOR SIMH)
 UARTCAS		.EQU	FALSE		; UART: AUTO-DETECT ECB CASSETTE UART
 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
-UARTDUO		.EQU	FALSE		; UART: AUTO-DETECT DUODYNE 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 70b84162..41da2e73 100644
--- a/Source/HBIOS/cfg_z80retro.asm
+++ b/Source/HBIOS/cfg_z80retro.asm
@@ -121,14 +121,13 @@ 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 ONBOARD UART
 UARTSBCFORCE	.EQU	FALSE		; UART: FORCE DETECTION OF SBC UART (FOR SIMH)
 UARTCAS		.EQU	FALSE		; UART: AUTO-DETECT ECB CASSETTE UART
 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
-UARTDUO		.EQU	FALSE		; UART: AUTO-DETECT DUODYNE 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 0d6531b5..839705d4 100644
--- a/Source/HBIOS/cfg_zeta.asm
+++ b/Source/HBIOS/cfg_zeta.asm
@@ -117,7 +117,6 @@ 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
-UARTDUO		.EQU	FALSE		; UART: AUTO-DETECT DUODYNE 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 8576c116..74d132bd 100644
--- a/Source/HBIOS/cfg_zeta2.asm
+++ b/Source/HBIOS/cfg_zeta2.asm
@@ -121,14 +121,13 @@ 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 ONBOARD UART
 UARTSBCFORCE	.EQU	FALSE		; UART: FORCE DETECTION OF SBC UART (FOR SIMH)
 UARTCAS		.EQU	FALSE		; UART: AUTO-DETECT ECB CASSETTE UART
 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
-UARTDUO		.EQU	FALSE		; UART: AUTO-DETECT DUODYNE UART
 ;
 ASCIENABLE	.EQU	FALSE		; ASCI: ENABLE Z180 ASCI SERIAL DRIVER (ASCI.ASM)
 ;
diff --git a/Source/HBIOS/std.asm b/Source/HBIOS/std.asm
index c772ac54..3afa8d36 100644
--- a/Source/HBIOS/std.asm
+++ b/Source/HBIOS/std.asm
@@ -810,19 +810,20 @@ INT_IM2PH7	.EQU	7	; PCF I2C
 ;
 ; DUO Z80 IM2 INTERRUPTS
 ; 
+INT_UART0	.EQU	7	; UART 0
+INT_UART1	.EQU	6	; UART 1 ?????
 INT_CTC0A	.EQU	0	; ZILOG CTC 0, CHANNEL A
 INT_CTC0B	.EQU	1	; ZILOG CTC 0, CHANNEL B
 INT_CTC0C	.EQU	2	; ZILOG CTC 0, CHANNEL C
 INT_CTC0D	.EQU	3	; ZILOG CTC 0, CHANNEL D
 INT_UART0	.EQU	4	; UART 0
 INT_UART1	.EQU	5	; UART 1
-INT_SIO0	.EQU	7	; ZILOG SIO 0, CHANNEL A & B
+;INT_SIO0	.EQU	7	; ZILOG SIO 0, CHANNEL A & B
 INT_SIO1	.EQU	8	; ZILOG SIO 1, CHANNEL A & B
 INT_PIO0A	.EQU	9	; ZILOG PIO 0, CHANNEL A
 INT_PIO0B	.EQU	10	; ZILOG PIO 0, CHANNEL B
 INT_PIO1A	.EQU	11	; ZILOG PIO 1, CHANNEL A
 INT_PIO1B	.EQU	12	; ZILOG PIO 1, CHANNEL B
-
   #ENDIF
 
   #IF ((PLATFORM != PLT_MBC) & (PLATFORM != PLT_DUO))
diff --git a/Source/HBIOS/uart.asm b/Source/HBIOS/uart.asm
index 633f4d6b..5deff4ac 100644
--- a/Source/HBIOS/uart.asm
+++ b/Source/HBIOS/uart.asm
@@ -53,13 +53,16 @@ UART_INTACT		.EQU	7	; INT RCV ACTIVE BIT
 UART_FIFOACT		.EQU	6	; FIFO ACTIVE BIT
 UART_AFCACT		.EQU	5	; AUTO FLOW CONTROL ACTIVE BIT
 ;
+#IF (PLATFORM == PLT_DUO)
+UARTSBASE		.EQU	$58
+#ELSE
 UARTSBASE		.EQU	$68
+#ENDIF
 UARTCBASE		.EQU	$80
 UARTMBASE		.EQU	$18
 UART4BASE		.EQU	$C0
 UARTRBASE		.EQU	$A0
 UARTDBASE		.EQU	$80
-UARTYBASE		.EQU	$58
 ;
 #IF (UARTINTS)
 ;
@@ -1088,16 +1091,6 @@ UART_CFG_MFP:
 	.DW	UARTCFG				; LINE CONFIGURATION
 	.DW	0				; SHOULD NEVER NEED INT HANDLER
 #ENDIF
-#IF (UARTDUO)
-UART_CFG_DUO:
-	; DUODYNE ONBOARD SERIAL PORT
-	.DB	0				; DEVICE NUMBER (UPDATED DURING INIT)
-	.DB	0				; UART TYPE
-	.DB	UARTYBASE			; IO PORT BASE (RBR, THR)
-	.DB	UARTYBASE + UART_LSR		; LINE STATUS PORT (LSR)
-	.DW	UARTCFG				; LINE CONFIGURATION
-	.DW	0				; POINTER TO RCV BUFFER STRUCT
-#ENDIF
 ;
 UART_CNT	.EQU	($ - UART_CFG) / 8
 ;
diff --git a/Source/ver.inc b/Source/ver.inc
index 17fe5ab8..d825e9f1 100644
--- a/Source/ver.inc
+++ b/Source/ver.inc
@@ -2,7 +2,7 @@
 #DEFINE	RMN	3
 #DEFINE	RUP	0
 #DEFINE	RTP	0
-#DEFINE BIOSVER	"3.3.0-dev.42"
+#DEFINE BIOSVER	"3.3.0-dev.43"
 #define rmj	RMJ
 #define rmn	RMN
 #define rup	RUP
diff --git a/Source/ver.lib b/Source/ver.lib
index c8a80e26..d0b3516b 100644
--- a/Source/ver.lib
+++ b/Source/ver.lib
@@ -3,5 +3,5 @@ rmn	equ	3
 rup	equ	0
 rtp	equ	0
 biosver	macro
-	db	"3.3.0-dev.42"
+	db	"3.3.0-dev.43"
 	endm