hook IRQ early, fix Berzap MB config

src/4cade.init.a

@@ -165,6 +165,11 @@
          jsr   init                  ; initialize and relocate ProRWTS2 to $D400 in RAM bank 2
                                      ; ProRWTS2 disk-data live at $D000-D3FF
          sei                         ; we're about to overwrite ProDOS's IRQ handler
+         lda   #<NOIRQ
+         sta   $3FE
+         lda   #>NOIRQ               ; in case another routine re-enables them
+         sta   $3FF
+         cli
          ldx   #$00                  ; relocate program code to top of language card
                                      ; since we end at $0000 now, adjust low offset to avoid destroying zpage
 @FM      lda   FirstMover - (RELBASE & $FF),x
@@ -282,6 +287,8 @@ FoundMockingboardCallback
          ora   #$B0
          jmp   ROM_COUT
 
+NOIRQ    rti
+
          !src  "src/4cade.branding.a"
          !src  "src/4cade.version.a"
 

src/prelaunch/berzap.mb.a

@@ -99,14 +99,14 @@ setopt
          ldy   #0
          sty   $382       ; joystick
          ldx   #2
-         iny              ; Sound/Speech I
+         iny
 
          +READ_RAM2_NO_WRITE
          bit   MockingboardStuff
-         bmi   +          ; SC-01
-         ldx   #0
-         dey              ; Sound II
-         bvc   +          ; no speech
+         bmi   +          ; Sounds / Speech (mono, SC-01)
+         dex
+         dey
+         bvc   +          ; Sound II / A (stereo, no speech)
          ldx   #4
          ldy   #2         ; Mockingboard "C"
 +        stx   $380