diff --git a/src/GLABIOS.ASM b/src/GLABIOS.ASM
index 81ca0e3..de4e6ec 100755
--- a/src/GLABIOS.ASM
+++ b/src/GLABIOS.ASM
@@ -528,10 +528,11 @@ SW1_FLP		=	00b			; SW1 7/8 Max # of floppy drives (0-3)
 	ENDIF
 
 ;----------------------------------------------------------------------------;
-; Configuration for Compaq XT (incomplete)
+; Configuration for Compaq Portable (incomplete)
 ;
 	IF ARCH_TYPE EQ ARCH_CPQ
 TURBO_TYPE		=	TURBO_NONE		; disable Turbo features
+POST_TEST_FD	=	0			; Avoid FDD 0800 error
 SW1_VID		=	10b			; SW1 5/6 ON/OFF Video Type CGA 80
 SW1_FLP		=	1			; SW1 7/8 Max # of floppy drives (0-3)
 							;  0-based: 0=1 drive, 1=2 drives, etc
@@ -7227,7 +7228,7 @@ INT_KB_IS_ALT_000:
 INT_KB_NOT_ALT_000:
 	XCHG	AX, BX					; restore AX
 	MOV	DI, OFFSET INT_KB_ALT_SKIP
-	MOV	CL, 10					; L_INT_KB_ALT_SKIP
+	MOV	CX, L_INT_KB_ALT_SKIP
 	XCHG	AH, AL
 	REPNE SCASB						; is in table?
 	XCHG	AH, AL
@@ -7308,7 +7309,10 @@ INT_KB_CTRL:
 INT_KB_CTRL_ALT:
 	CMP	AH, 53H					; is Ctrl-Alt-Del?
 			IF IS_TURBO
-	JNE	INT_KB_CTRL_ALT_1				; if not check for turbo hotkey
+	JNZ	INT_KB_CTRL_ALT_1				; if not check for turbo hotkey
+			ENDIF
+			IF ARCH_TYPE EQ ARCH_CPQ
+	JNZ	INT_KB_CTRL_ALT_2				; jump to compaq key commands
 			ELSE
 	JNE	INT_KB_CTRL_NO_DONE			; put in buffer as-is and exit
 			ENDIF
@@ -7337,7 +7341,7 @@ INT_KB_CTRL_ALT_DEL:
 
 			IF IS_TURBO
 ;----------------------------------------------------------------------------;
-; 10. Handle Ctrl-Alt but not Del (only Turbo hotkey)
+; 10. Handle Ctrl-Alt but not Del
 ;
 INT_KB_CTRL_ALT_1:
 
@@ -7378,6 +7382,29 @@ INT_KB_TOGGLE_TURBO PROC
 INT_KB_TOGGLE_TURBO ENDP
 			ENDIF
 
+
+                  IF ARCH_TYPE EQ ARCH_CPQ
+INT_KB_CTRL_ALT_2:
+;----------------------------------------------------------------------------;
+; Ctrl-Alt-, CGA 80x25
+;
+      CMP   AH, 33H
+	JNZ	INT_KB_CTRL_ALT_3
+	CALL	CPQ_VID_CGA
+	JMP	SHORT INT_KB_DONE_3
+
+;----------------------------------------------------------------------------;
+; Ctrl-Alt-. MDA 80x25
+;
+INT_KB_CTRL_ALT_3:
+      CMP   AH, 34H
+	JNZ	INT_KB_CTRL_NO_DONE
+	CALL	CPQ_VID_MDA
+	JMP	SHORT INT_KB_DONE_3
+
+                  ENDIF
+
+
 ;----------------------------------------------------------------------------;
 ; 5. Is a flag key?
 ;----------------------------------------------------------------------------;
@@ -7550,8 +7577,10 @@ INT_KB_ALT_SKIP	LABEL BYTE
 	DB	28H					; '
 	DB	29H					; `
 	DB	2BH					; \
+			IF ARCH_TYPE NE ARCH_CPQ
 	DB	33H					; ,
 	DB	34H					; .
+			ENDIF
 	DB	35H					; /
 	DB	37H					; * PrcSc
 L_INT_KB_ALT_SKIP	EQU $-INT_KB_ALT_SKIP
@@ -9119,7 +9148,8 @@ O_INT_1D_40		EQU	INT_1D_40-INT_1D		; 40x25 mode data offset
 
 ; 80x25 CGA text
 		IF ARCH_TYPE EQ ARCH_CPQ
-INT_1D_80		CRTC	<71H,50H,5AH,0AH,19H,06H,19H,19H,02H,0DH,0BH,0CH>
+INT_1D_80		CRTC	<71H,50H,5AH,0AH,19H,06H,19H,19H,02H,0DH,0BH,0CH>	; MDA-like (default)
+INT_1D_80_CGA	CRTC	<71H,50H,5AH,0AH,1FH,06H,19H,1CH,02H,07H,06H,07H>	; standard CGA
 		ELSE
 INT_1D_80		CRTC	<71H,50H,5AH,0AH,1FH,06H,19H,1CH,02H,07H,06H,07H>
 		ENDIF
@@ -9226,7 +9256,7 @@ INT_10_0_IS_CGA:
 ;----------------------------------------------------------------------------;
 ; Is CGA graphics (modes 4-6)
 ;
-	SHL	SI, 1					; SI = CGA GFX CRTD offset (20H)
+	MOV	SI, O_INT_1D_GFX			; SI = CGA GFX CRTD offset
 	MOV	AH, HIGH CGA_MEM_SZ		; CGA gfx page size = 4000H (16K)
 	XOR	DI, DI				; DI = memory fill 0's
 	TEST	BL, 0010B				; is 80 or 40 col text?
@@ -12200,6 +12230,33 @@ INT_10_4_GFX:
 INT_10_4 ENDP
 		ENDIF				; /LIGHT_PEN EQ 1
 
+		IF ARCH_TYPE EQ ARCH_CPQ
+;----------------------------------------------------------------------------;
+; Compaq Portable video style switch (Ctrl-Alt-, / Ctrl-Alt-.)
+;----------------------------------------------------------------------------;
+; The Compaq Portable has a dual sync internal monitor paired with a Compaq
+; VDU that can display MDA & CGA timings. In 80x25 mode it will default to
+; MDA-like mode, but can be switched back and forth via keyboard commands.
+; CRTC timings drive the VDU without any video mode change, screen clear, etc.
+;----------------------------------------------------------------------------;
+CPQ_VID_CGA:
+	MOV	SI, OFFSET INT_1D_80_CGA		; standard CGA 80x25 timing
+	JMP	SHORT CPQ_VID_SET
+CPQ_VID_MDA:
+	MOV	SI, OFFSET INT_1D_80			; MDA-like 80x25 timing (boot default)
+CPQ_VID_SET:
+	MOV	DX, VID_PORT
+	XOR	AX, AX
+	MOV	CX, 12
+CPQ_VID_LOOP:
+	MOV	AH, CS:[SI]
+	OUT	DX, AX
+	INC	AX
+	INC	SI
+	LOOP	CPQ_VID_LOOP
+	RET
+		ENDIF
+
 ;
 ; 79 BYTES HERE / 0 BYTES HERE 5150
 ;