diff --git a/bitsy.boot.s b/bitsy.boot.s
index 5991600..75a4136 100644
--- a/bitsy.boot.s
+++ b/bitsy.boot.s
@@ -18,6 +18,7 @@ MLI_ENTRY       := $BF00
 DEVNUM          := $BF30
 DEVCNT          := $BF31
 DEVLST          := $BF32
+MACHID          := $BF98
 
 KBD             := $C000
 CLR80VID        := $C00C
@@ -67,7 +68,7 @@ L2036:  dey
 ; display splash screen
 
         jsr     HOME
-        ldx     #(END_SPLASH - SPLASH_SCREEN)        ;#$9D
+        ldx     #(END_SPLASH - SPLASH_SCREEN)
 L203E:  lda     SPLASH_SCREEN-1,x
         bmi     L204A
         jsr     BASCALC
@@ -92,7 +93,7 @@ L205A:  txa
         lda     #$10
         sta     $29
         sta     KBDSTRB         ; clear keyboard strobe
-        bne     MAIN_LOOP           ; branch-always to MAIN_LOOP
+        bne     MAIN_LOOP       ; branch-always to MAIN_LOOP
 
 ; get keypress and process
 
@@ -100,27 +101,39 @@ MAIN_LOOP_WITH_BEEP:
         jsr     ROM_BELL
 MAIN_LOOP:
         jsr     RDKEY
-.ifndef PLUS_FIX
-        bit     RDBTN0          ; open-apple -- this fries the franklin?
-        bmi     QUIT
-.endif
-        cmp     #$B8            ; >= 8?
-        bcs     QUIT
-        cmp     #$B1            ; >= 1?
-        bcs     SET_SLOT_AND_BOOT
         cmp     #$9B            ; ESC?
-        beq     L209B
+        beq     DO_MLI_BOOT
         cmp     #$8D            ; CR?
         beq     BOOT_RECENT
         cmp     #$A0            ; space?
-.ifndef PLUS_FIX
-        bne     MAIN_LOOP
-.else
         beq     BOOT_RECENT
-        bit     RDBTN0          ; open-apple -- this fries the franklin?
-        bmi     QUIT
+        cmp     #$B8            ; >= 8?
+        bcs     GSOS_QUIT
+        cmp     #$B1            ; >= 1?
+        bcs     SET_SLOT_AND_BOOT
+GSOS_QUIT:
+        ldx     MACHID
+        cpx     #$b3            ; IIgs (or //e with clock card)
+        bne     MAIN_LOOP_WITH_BEEP
+        bit     RDBTN0          ; safe to check O-A now
         bpl     MAIN_LOOP
-.endif
+        and     #$DF
+        cmp     #$D1            ; Q? (GS/OS only)
+        bne     MAIN_LOOP_WITH_BEEP
+
+; 65816 GS/OS gunk here ...
+.setcpu "65816"
+        rep     #$80            ; reset processor status bits
+        bmi     MAIN_LOOP_WITH_BEEP
+        lda     $E100BD         ; OS_BOOT (byte)
+        dec
+        bne     MAIN_LOOP_WITH_BEEP
+        clc
+        xce                     ; swap carry and emulation flags (clear E)
+        lda     LCBANK1         ; rw:LCBANK1
+        jmp     $E0D000
+.setcpu "6502"
+
 BOOT_RECENT:
         jsr     GET_SLOT
 
@@ -130,39 +143,15 @@ SET_SLOT_AND_BOOT:
         ora     #$C0            ; this becomes $C100-$C700
         sta     BOOTVEC+2       ; and put it into boot vector
 
-L209B:  jsr     HOME
+DO_MLI_BOOT:
+        jsr     HOME
 BOOTVEC:
         jsr     MLI_ENTRY       ; but overwritten to slot entry point
         .byte   $65
         .word   * + 2
         .byte   $04             ; it's apparently okay to have garbage for $65
 
-QUIT:
-        cmp     #$9B            ; key ESC?
-        beq     L20AF
-        and     #$DF
-        cmp     #$D1            ; key Q?
-        bne     MAIN_LOOP_WITH_BEEP
-L20AF:  bit     RDBTN0          ; is open-apple pressed?
-        bpl     MAIN_LOOP_WITH_BEEP           ; if not, restart loop
-
-; 65816 GS/OS gunk here ...
-
-.setcpu "65816"
-        REP     #$80
-        BMI     MAIN_LOOP_WITH_BEEP
-        LDA     $E100BD         ;  OS_BOOT (byte)
-        DEC
-        BNE     MAIN_LOOP_WITH_BEEP
-        CLC
-        XCE
-        LDA     LCBANK1         ; rw:LCBANK1
-        JMP     $E0D000
-
-.setcpu "6502"
-
 ; get last-accessed slot
-
 GET_SLOT:
         lda     DEVNUM
         lsr     a