ReadWithRWTS
         lda   #$22
         jsr   ChangeTrackNW
         lda   #$0F
         ldx   gIs13Sector
         bne   +
         lda   #$0C
+        jsr   ChangeSector
         lda   #<T22S0F
         sta   checksector+1
         lda   #>T22S0F
         sta   checksector+2
.read
         lda   KEY
         bpl   .checkinfocom
         bit   STROBE
         cmp   #$e0 ;ignore backtick (MAME debug break)
         beq   .checkinfocom
         jmp   Cancel
.checkinfocom
         lda   gIsInfocom18
         bne   checksector
         jsr   VerifyInfocom18
         bcc   .passtrack
         jmp   FatalError
.passtrack
         jmp   .prevtrack

checksector
         lda   $FFFF                            ; status of current sector in sector map (modified above)
         cmp   #kSectorCustomFirst              ; call a custom routine before deciding what to do with this sector?
         bcc   +
         cmp   #kSectorCustomLast
         bcs   +
         jsr   PreReadSector
+        pha                                    ; replace status (on stack) with new status returned from PreReadSector
         cmp   #kSectorIgnore                   ; skip this sector?
         beq   nextsector
         cmp   #kSectorSwitchToBuiltinRWTS      ; switch to built-in RWTS before reading this sector?
         bne   +
         lda   gTriedUniv
         beq   +
         jsr   SwitchToUniv
+        jsr   ReadSector
         bcc   nextsector
;
; Uh oh, we got a read error. But do we care?
; If we just got to this track, check for whole-track protections.
;
         ldx   #$0F ;16-sector
         lda   gIs13Sector
         beq   .expect13
         lda   gIsDOS32
         bne   +
.expect13
         ldx   #$0C ;13-sector
+        cpx   gSector
         bne   .checkoptional
         stx   .sub+1
         jsr   SkipTrack
         bcs   .checkoptional
; Skip this track (we already printed the reason)
         lda   #$00
         jsr   ChangeSector
         lda   checksector+1
         sec
.sub     sbc   #$0F ;self-modified according to sectors per track
         sta   checksector+1
         bcs   +
         dec   checksector+2
+        jmp   nextsector

; do this only *after* checking for track-skip
; to avoid fatal errors on unformatted tracks

.checkoptional
         pla
         pha
;
; Maybe we marked this sector as optional based
; on markers in the bootloader.
;
         cmp   #kSectorOptional
         beq   .optional

;
; Otherwise we're in the middle of a track, so try switching to
; the universal RWTS and see if that helps. (Many disks contain
; an RWTS that can't read the early tracks or sectors that
; contain the RWTS code, since those are loaded by the
; disk controller firmware.)
;

.tryuniversal
         lda   gIsDOS32   ; is this a DOS 3.2 disk?
         beq   .fatal     ; yes, so read error is fatal
         lda   gTriedUniv ; have we tried the universal RWTS?
         beq   .maybedavidson ; yes, but check one last thing
         jsr   SwitchToUniv ; no, switch it in now
         jmp   .read      ; and re-read this sector

.maybedavidson
         jsr   IDDavidson
         bcc   .optional

.fatal   pla              ; if we get to here, we've
         jmp   FatalError ; decided the read error is fatal

.optional
         lda   #s_optbad  ; say we're skipping this
         jsr   PrintByID  ; optional sector
         ; /!\ execution falls through here

nextsector
         pla
         lda   checksector+1
         bne   .nodec
         dec   checksector+2
.nodec
         dec   checksector+1
         ldy   gSector
         dey
         tya
         jsr   ChangeSector
         lda   gSector
         bmi   .prevtrack
.linkread
         jmp   .read
.prevtrack
         lda   #$0F
         ldx   gIs13Sector
         bne   +
         lda   #$0C
+        jsr   ChangeSector
         ldy   gTrack
         dey
         tya
         jsr   ChangeTrack
         jsr   IncProgress
         lda   gTrack
         bmi   Pass
         cmp   gLastTrack
         bcs   .linkread
Pass
         bit   gMode
         bpl   @passVerify
         lda   gRAMDiskRef
         beq   @printFinalMessage    ; not using RAM disk, so we're done

         ; we've written the entire cracked disk as a file on the RAM disk,
         ; now a second pass to write that file out to the target disk drive
         lda   #s_writingto
         jsr   PrintByID
         lda   #s_slotanddrive
         jsr   PrintByID
         jsr   SwapProDOS            ; ProDOS out -> in
         jsr   WriteRAMToDisk
         jsr   SwapProDOS            ; ProDOS in -> out (preserves flags)
         bcc   @printFinalMessage
         jmp   FatalWriteError

@printFinalMessage
         lda   gPatchCount
         beq   @passWithZeroPatches
         lda   #s_passcrack          ; 'crack complete'
         !byte $2C
@passWithZeroPatches
         lda   #s_passcrack0         ; 'crack complete but no patches'
         !byte $2C
@passVerify
         lda   #s_pass               ; 'verification complete'
         jsr   PrintByID
         jmp   TheEnd

Cancel
         lda   #s_canceled
         jsr   PrintByID
         jmp   TheEnd

FatalError
         lda   #s_fail
         jsr   PrintByID
         lda   gTrack
         cmp   #$22
         bne   @TheEnd
         lda   gSector
         cmp   #$0F
         beq   @failont22s0f
         ldx   gIsDOS32
         bne   @TheEnd
         cmp   #$0C
         bne   @TheEnd
@failont22s0f
         lda   #s_fatal220f
         jsr   PrintByID
@TheEnd  jmp   TheEnd