Difference between revisions of "Hollywood Collection"

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Line 48: Line 48:
 
| Verified by || enigma
 
| Verified by || enigma
 
|}
 
|}
−
 
−
[[File:Ghostbusters_ii_disk.jpg|thumb|Ghostbusters II Disk]]
 
−
 
 
<gallery>
 
<gallery>
 
File:GhostbustersII_a_enigma_dos_r1.png|Side 0
 
File:GhostbustersII_a_enigma_dos_r1.png|Side 0
 
File:GhostbustersII_b_enigma_dos_r1.png|Side 1
 
File:GhostbustersII_b_enigma_dos_r1.png|Side 1
 +
</gallery>
 +
<gallery>
 +
File:Ghostbusters_ii_disk.jpg|Ghostbusters II Disk
 
</gallery>
 
</gallery>
 
<gallery>
 
<gallery>
Line 65: Line 65:
 
==== G64 ====
 
==== G64 ====
 
===== Disk 4 =====
 
===== Disk 4 =====
−
Protection: [[GMA89]]
+
Mastered with a cracked GMA89 protection, see discussion at the end of this page
  
 
[[File:GhostbustersII_s0.g64]]
 
[[File:GhostbustersII_s0.g64]]
Line 106: Line 106:
 
| Verified by || enigma
 
| Verified by || enigma
 
|}
 
|}
−
 
+
<gallery>
−
[[File:HollywoodCollection_Disk3_jupp3_a_dos_r1.png|thumb|Side 0]]
+
File:HollywoodCollection_Disk3_jupp3_a_dos_r1.png|Side 0
−
 
+
</gallery>
 
<gallery>
 
<gallery>
 
File:HollywoodCollection_Disk3_Label.jpg|Disk Label
 
File:HollywoodCollection_Disk3_Label.jpg|Disk Label
Line 115: Line 115:
 
File:HollywoodCollection_Disk3_jupp3_indy.png|Indiana Jones and the Last Crusade: The Action Game
 
File:HollywoodCollection_Disk3_jupp3_indy.png|Indiana Jones and the Last Crusade: The Action Game
 
</gallery>
 
</gallery>
−
 
 
Purchased from: From the collection of J-P.J.
 
Purchased from: From the collection of J-P.J.
 
==== Streams ====
 
==== Streams ====
Line 202: Line 201:
 
[[File:Streams_HollywoodCollection_disk3_rakki.zip]]
 
[[File:Streams_HollywoodCollection_disk3_rakki.zip]]
 
===== Disk 4 =====
 
===== Disk 4 =====
−
Protection: [[GMA89]]
+
Mastered with a cracked GMA89 protection, see discussion at the end of this page
  
 
[[File:Streams_HollywoodCollection_disk4_rakki.zip]]
 
[[File:Streams_HollywoodCollection_disk4_rakki.zip]]
Line 293: Line 292:
 
[[File:Streams_HollywoodCollection_Ocean_incomplete_disk3_rakki.zip]]
 
[[File:Streams_HollywoodCollection_Ocean_incomplete_disk3_rakki.zip]]
 
===== Disk 4 =====
 
===== Disk 4 =====
−
Protection: [[GMA89]]
+
Mastered with a cracked GMA89 protection, see discussion at the end of this page
  
 
[[File:Streams_HollywoodCollection_Ocean_incomplete_disk4_rakki.zip]]
 
[[File:Streams_HollywoodCollection_Ocean_incomplete_disk4_rakki.zip]]
Line 367: Line 366:
 
Disk 3 [[Indiana Jones and the Last Crusade: The Action Game]]: Protection: [[CYAN Loader A]]
 
Disk 3 [[Indiana Jones and the Last Crusade: The Action Game]]: Protection: [[CYAN Loader A]]
  
−
Disk 4 [[Ghostbusters II]]: Protection: [[GMA89]]
+
Disk 4 [[Ghostbusters II]]: Mastered with a cracked GMA89 protection, see discussion at the end of this page
 
==== SCP ====
 
==== SCP ====
 
[[File:SCP_Compilation Hollywood Collection_quader.zip]]
 
[[File:SCP_Compilation Hollywood Collection_quader.zip]]
Line 456: Line 455:
  
 
[[File:HollywoodCollection_Disk3_Ocean_parser_s0.g64]]
 
[[File:HollywoodCollection_Disk3_Ocean_parser_s0.g64]]
 +
 +
= Hollywood Collection Ghostbusters II vs Release Ghostbusters II =
 +
 +
'''Disk 4''' of the ''Hollywood Collection'' compilation contains a copy of
 +
'''Ghostbusters II''' — the same game documented under its own
 +
GMA89-protected release, which uses the standard family mechanism
 +
(sync-length signature measured on track 38, sent to the C64, used as a
 +
single repeating-byte XOR decryption key). For Hollywood Collection's
 +
live tracing and static disk analysis both found
 +
'''no functioning protection check at all''' in any locally-archived copy.
 +
 +
Having a genuine, actively-protected Ghostbusters II source
 +
(<code>GhostbustersII_zrx_s0.g64</code>, measured key <code>$18</code>) and
 +
Hollywood Collection's Disk 4 side by side made it possible to find not
 +
just ''that'' the protection was removed, but the '''exact two-instruction
 +
patch''' that removed it.
 +
 +
== Summary ==
 +
 +
* The genuine disk's directory is deliberately near-empty and obfuscated (<code>as</code>, <code>gm1</code>, <code>side flag</code> only, BAM reporting <code>0 blocks free</code>) — the standard GMA-family convention. Hollywood Collection's Disk 4 directory is completely ordinary and legible, with individually-named game asset files and one conspicuous extra entry, <code>gmaread.src.mod</code>.
 +
* <code>gm1.prg</code> is 4 bytes shorter than the genuine version (1440 vs. 1444 bytes) and otherwise byte-for-byte identical apart from address shifts caused by two edits.
 +
* '''Edit 1:''' the <code>JSR $C800</code> instruction (the fixed drive-upload-and-execute trigger used throughout the whole GMA family) is deleted outright — not bypassed, not patched to skip on a flag, simply removed. The drive never seeks to track 38 at all.
 +
* '''Edit 2:''' a single opcode byte inside the decrypt loop — <code>EOR $D000,Y</code> (<code>$59</code>) changed to <code>LDA $D000,Y</code> (<code>$B9</code>) — turns the XOR-decrypt pass into a harmless no-op self-copy.
 +
* The disk's own game data was correspondingly re-saved as already-decrypted plaintext, matching the now-legible directory.
 +
* <code>gmaread.src.mod</code> is an inert leftover file (bogus <code>$FFFF</code> load address, never actually loaded) containing recognizable fragments of the removed drive-upload routine — almost certainly the cracker's own extracted copy of the code they cut out.
 +
 +
== Directory comparison ==
 +
 +
Genuine Ghostbusters II source (protection active):
 +
 +
<pre>
 +
0 "gbii            "
 +
0    "as"              prg
 +
0    "gm1"              prg
 +
1    "side flag"        prg
 +
0 blocks free.
 +
</pre>
 +
 +
Hollywood Collection, Disk 4 (protection removed):
 +
 +
<pre>
 +
0 "gbii            " pj 2a
 +
1    "as"              prg
 +
2    "gmaread.src.mod"  prg
 +
6    "gm1"              prg
 +
4    "mask2"            prg
 +
4    "mask1"            prg
 +
24  "vigosm image"    prg
 +
24  "janosz image"    prg
 +
24  "venkdana image"  prg
 +
5    "vii text"        prg
 +
4    "win text"        prg
 +
14  "music b"          prg
 +
1    "side flag"        prg
 +
17  "music a"          prg
 +
9    "gbiichars"        prg
 +
121  "vigo 0800-8000"  prg
 +
81  "vigo 8000-cfff"  prg
 +
5    "vigo fc00-ffff"  prg
 +
5    "gm2"              prg
 +
313 blocks free.
 +
</pre>
 +
 +
The genuine disk's near-empty, obfuscated directory (real content hidden
 +
outside the normal directory chain, BAM deliberately reporting the disk as
 +
full) is the standard GMA-family convention documented throughout this
 +
project. Hollywood Collection's directory is a completely ordinary,
 +
legible file listing — the game's graphics, music, and code blocks are all
 +
individually named and directly loadable, consistent with data that no
 +
longer needs a decrypt step at load time.
 +
 +
== Edit 1: the upload trigger is deleted, not bypassed ==
 +
 +
<pre>
 +
;; ---- genuine (protection active) ----
 +
L03A6:  BNE L03A6
 +
        LDA #$37
 +
        STA $01
 +
        LDA #$00
 +
        JSR sub_0461        ; load file 0
 +
        JSR $C800            ; <=== upload + execute the drive-side
 +
                              ;      signature check, collect measured
 +
                              ;      key byte in A
 +
        PHA                  ; stash the REAL measured key
 +
        LDA #$01
 +
        JSR sub_0461          ; load file 1
 +
        ...
 +
 +
;; ---- Hollywood Collection Disk 4 (patched) ----
 +
L03A6:  BNE L03A6
 +
        LDA #$37
 +
        STA $01
 +
        LDA #$00
 +
        JSR sub_045E          ; load file 0 (same routine, renamed by the
 +
                              ;  disassembler only because addresses shifted)
 +
        PHA                  ; <=== stashes whatever A happened to hold
 +
                              ;      after the LOAD call - NOT a measured
 +
                              ;      key. The entire "JSR $C800" instruction
 +
                              ;      (bytes 20 00 C8) is simply gone.
 +
        LDA #$01
 +
        JSR sub_045E          ; load file 1
 +
        ...
 +
</pre>
 +
 +
Confirmed at the raw byte level: searching the genuine file for
 +
<code>20 00 C8</code> (<code>JSR $C800</code>) finds it at file offset 127;
 +
the identical search against Hollywood Collection's <code>gm1.prg</code>
 +
finds '''nothing''' anywhere in the file. The 3-byte call was cut out
 +
entirely, not disabled by a patched branch or a flag check — the loader's
 +
control flow simply never reaches the drive-side code at all.
 +
 +
== Edit 2: a single-byte opcode patch neutralizes the decrypt loop ==
 +
 +
Even though nothing meaningful reaches it after Edit 1, the decrypt loop
 +
still runs — over whatever garbage value the removed <code>JSR $C800</code>
 +
would otherwise have replaced with a real key:
 +
 +
<pre>
 +
;; ---- genuine ----
 +
        TXA
 +
        EOR $D000,Y    ; 8A 59 00 D0  - actual XOR decrypt against the
 +
        STA $D000,Y    ; 99 00 D0      key in X, byte by byte
 +
 +
;; ---- Hollywood Collection Disk 4 ----
 +
        TXA
 +
        LDA $D000,Y    ; 8A B9 00 D0  - reads the byte and immediately
 +
        STA $D000,Y    ; 99 00 D0      overwrites A, discarding the
 +
                          ;              "key" TXA just loaded - net
 +
                          ;              effect: read byte, write the
 +
                          ;              same byte back unchanged
 +
</pre>
 +
 +
One byte — <code>$59</code> (<code>EOR abs,Y</code>) changed to
 +
<code>$B9</code> (<code>LDA abs,Y</code>) — turns the entire decrypt pass
 +
into a no-op self-copy loop.
 +
 +
== The leftover: <code>gmaread.src.mod</code> ==
 +
 +
A 374-byte file present only on Hollywood Collection's Disk 4, with a
 +
bogus <code>$FFFF</code> load address header — meaning nothing ever
 +
actually loads it; it just sits in the directory unused. Its content is
 +
unmistakably recognizable as fragments of the family's standard drive-side
 +
upload machinery: the <code>M-W</code> chunk-upload loop that builds a
 +
memory-write command byte by byte, and — near the end of the file — the
 +
exact <code>LDA $1C00 / AND #$9F / STA $1C00</code> IEC-bus-initialization
 +
sequence that opens every drive-side program documented throughout this
 +
project's GMA-family investigations. This is almost certainly the
 +
cracker's own extracted copy of the code removed from <code>gm1.prg</code>
 +
in Edit 1 above — kept as a personal reference or backup rather than
 +
deleted, and an incidental second confirmation of the shared drive-side
 +
routine's own opening bytes for a title otherwise absent from every other
 +
cross-check in the GMA89 survey.
 +
 +
== Conclusion ==
 +
 +
Hollywood Collection's Disk 4 is a clean, complete crack of Ghostbusters
 +
II's GMA89 protection — not an alternate build that never had one, and not
 +
evidence against anything documented elsewhere about the mechanism itself.
 +
The crack:
 +
 +
# Removes the drive-upload trigger, so the drive never seeks to track 38 at all (matching the D64-conversion and live-boot results that first flagged this disk as having no functioning check).
 +
# Neutralizes the decrypt loop as a defense-in-depth measure, even though by that point it's only ever fed garbage.
 +
# Replaces the on-disk data with its already-decrypted plaintext, matching the disk's now-ordinary, legible directory.
 +
 +
Ghostbusters II's own dedicated GMA89 sources remain the correct place to
 +
find this game's actual measured key (<code>$18</code>); Hollywood
 +
Collection's Disk 4 is documented here specifically as a case study in what
 +
a complete GMA-family crack looks like at the byte level, not as a fourth
 +
source for the key.

Latest revision as of 00:09, 29 August 2026

mobygames link

Contents

Disk 1
Disk 2
Disk 3
Disk 4

The german release of the compilation does not include Robocop.

Source 1

Property Data
Title Hollywood Collection
Publisher and/or Developer Ocean Software Ltd.
Year 1990
Disk(s) 4?
Number of Index Holes 2
Media Type 5.25 DSDD
Retail, Budget or Compilation (with name) Compilation
Country of Release UK
Language(s) English
Platform C64
NTSC or PAL PAL
Protection see streams section
Working? Yes, but incomplete
Archived 24 Oct 2014 enigma
Verified by enigma

  • Side 0

  • Side 1

  • Ghostbusters II Disk

  • Ghostbusters II Title

  • Ghostbusters II Intro

  • Ghostbusters II Game

Streams

Disk 4

File:Streams GhostbustersII enigma.zip

G64

Disk 4

Mastered with a cracked GMA89 protection, see discussion at the end of this page

File:GhostbustersII s0.g64

File:GhostbustersII s1.g64

Source 2

Property Data
Title Hollywood Collection
Publisher and/or Developer Ocean Software Ltd.
Year 1990
Disk(s) 4?
Number of Index Holes 1
Media Type 5.25 DSDD
Retail, Budget or Compilation (with name) Compilation
Country of Release UK
Language(s) English
Platform C64
NTSC or PAL PAL
Protection see streams section
Working? Yes, but incomplete
Archived 19 Oct 2013 jupp3
Verified by enigma

  • Side 0

  • Disk Label

  • Indiana Jones and the Last Crusade: The Action Game

Purchased from: From the collection of J-P.J.

Streams

Disk 3

File:Streams HollywoodCollection incomplete disk3 jupp3.zip

G64

Disk 3

Protection: CYAN Loader A

File:HollywoodCollection Disk3 jupp3 s0.g64

Source 3

Property Data
Title Hollywood Collection
Publisher and/or Developer Ocean Software Ltd.
Year 1990
Disk(s) 4
Number of Index Holes 2, 1, 1, 2
Media Type 5.25 DSDD
Retail, Budget or Compilation (with name) Compilation
Country of Release UK
Language(s) English
Platform C64
NTSC or PAL PAL
Protection see streams section
Working? Yes
Archived 24 Jun 2013 Rakki
Verified by enigma

  • Disk 1 Side 0

  • Disk 1 Side 1

  • Disk 2 Side 0

  • Disk 3 Side 0

  • Disk 4 Side 0

  • Disk 4 Side 1

  • Box Front

  • Box Back

  • Box Content

  • Disk 1

  • Disk 1 Label

  • Disk 2

  • Disk 2 Label

  • Disk 3

  • Disk 3 Label

  • Disk 4

  • Disk 4 Label

  • ISBN Number

  • Manual Side A

  • Manual Side B

Purchased from: Tori.fi

Rakki: CIB

Streams

Disk 1

Protection: None

File:Streams HollywoodCollection disk1 rakki.zip

Disk 2

Protection: Ocean Protection

File:Streams HollywoodCollection disk2 rakki.zip

Disk 3

Protection: CYAN Loader A

File:Streams HollywoodCollection disk3 rakki.zip

Disk 4

Mastered with a cracked GMA89 protection, see discussion at the end of this page

File:Streams HollywoodCollection disk4 rakki.zip

G64

Disk 1

File:HollywoodCollection Disk1 rakki s0.g64

File:HollywoodCollection Disk1 rakki s1.g64

Disk 2

File:HollywoodCollection Disk2 rakki s0.g64

Disk side 1 is empty.

Disk 3

File:HollywoodCollection Disk3 rakki s0.g64

Disk side 1 is empty.

Disk 4

File:HollywoodCollection Disk4 rakki s0.g64

File:HollywoodCollection Disk4 rakki s1.g64

Source 4

Property Data
Title Hollywood Collection
Publisher and/or Developer Ocean Software Ltd.
Year 1990
Disk(s) 4
Number of Index Holes (2, 1), -, 1, 1
Media Type 5.25 DSDD
Retail, Budget or Compilation (with name) Compilation
Country of Release UK (DE? see comment)
Language(s) English
Platform C64
NTSC or PAL PAL
Protection see streams section
Working? Yes, but incomplete? (see comment)
Archived 4 Dec 2013 Rakki
Verified by enigma

  • Disk 1 Side 0

  • Disk 1 Side 1

  • Disk 1 2nd Copy Side 0

  • Disk 1 2nd Copy Side 1

  • Disk 3 Side 0

  • Disk 4 Side 0

  • Disk 4 Side 1

  • Disks

  • Disk 1

  • Disk 1 2nd Copy

  • Disk 3

  • Disk 4

Purchased from: ebay.de / sebkotska

Rakki: Loose. Disk 2 missing.

enigma: It could be that the disks originate from the german release of the compilation. In that case disk 2 with Robocop was not part of the compilation.

Streams

Disk 1

Protection: None

File:Streams HollywoodCollection Ocean incomplete disk1 rakki.zip

File:Streams HollywoodCollection Ocean incomplete 2nd copy disk1 rakki.zip

Disk 2

Missing

Disk 3

Protection: CYAN Loader A

File:Streams HollywoodCollection Ocean incomplete disk3 rakki.zip

Disk 4

Mastered with a cracked GMA89 protection, see discussion at the end of this page

File:Streams HollywoodCollection Ocean incomplete disk4 rakki.zip

G64

Disk 1

File:HollywoodCollection alt Disk1 rakki s0.g64

File:HollywoodCollection alt Disk1 rakki s1.g64

File:HollywoodCollection alt Disk1 2nd copy rakki s0.g64

File:HollywoodCollection alt Disk1 2nd copy rakki s1.g64

Disk 2

Missing

Disk 3

File:HollywoodCollection alt Disk3 rakki s0.g64

Disk side 1 is empty.

Disk 4

File:HollywoodCollection alt Disk4 rakki s0.g64

File:HollywoodCollection alt Disk4 rakki s1.g64

Source 5

Property Data
Title Hollywood Collection
Publisher and/or Developer Ocean Software Ltd.
Year 1990
Disk(s) 3
Number of Index Holes 2, -, 2, 1
Media Type 5.25 DSDD
Retail, Budget or Compilation (with name) Compilation
Country of Release DE
Language(s) English
Platform C64
NTSC or PAL PAL
Protection see streams section
Working? Yes
Archived 8 Nov 2020 Quader
Verified by enigma

  • Box Front

  • Box Back

  • Box Content

  • Disk 1

  • Disk 3

  • Disk 4

The german release of the compilation does not include disk 2 with Robocop.

For Disk 3 a second disk was dumped as well.

Protection

Disk 1 Batman: Protection: None

Disk 3 Indiana Jones and the Last Crusade: The Action Game: Protection: CYAN Loader A

Disk 4 Ghostbusters II: Mastered with a cracked GMA89 protection, see discussion at the end of this page

SCP

File:SCP Compilation Hollywood Collection quader.zip

enigma: In the SCPs the back side of Batman was modified. It also has an error 5 on track 20 in the data area of the game.

NBZ

File:NBZ Compilation Hollywood Collection quader.zip

G64

Disk 1

File:Batman - The Movie - Compilation Hollywood Collection - Disk A - SCP.g64

File:Batman - The Movie - Compilation Hollywood Collection - Disk B - NBZ.g64

Disk 2

Missing

Disk 3

File:Indiana Jones 3 - Compilation Hollywood Collection - A -SCP.g64

File:Indiana Jones 3 - Compilation Hollywood Collection - 2ndCopy - A -SCP.g64

Disk side 1 is empty.

Disk 4

File:Ghostbusters 2 - Compilation Hollywood Collection - A - SCP.g64

File:Ghostbusters 2 - Compilation Hollywood Collection - B - SCP.g64

Additional Information

Manuals

Scans by quader.

Manual Batman - The Movie

  • Indiana Jones 3 Flyer

Manual Indiana Jones 3
Manual Ghostbusters 2


Source 6

Property Data
Title Hollywood Collection
Publisher and/or Developer Ocean Software Ltd.
Year 1990
Disk(s) 4
Number of Index Holes 1
Media Type 5.25 DSDD
Retail, Budget or Compilation (with name) Compilation
Country of Release UK
Language(s) English
Platform C64
NTSC or PAL PAL
Protection see streams section
Working? Yes, but incomplete
Archived 17 Jul 2021 parser
Verified by enigma

  • Side 0

  • Disk

  • Disk with Sleeve

Streams

Disk 3

File:Streams HollywoodCollection Disk3 Ocean parser.zip

G64

Disk 3

Protection: CYAN Loader A

File:HollywoodCollection Disk3 Ocean parser s0.g64

Hollywood Collection Ghostbusters II vs Release Ghostbusters II

Disk 4 of the Hollywood Collection compilation contains a copy of Ghostbusters II — the same game documented under its own GMA89-protected release, which uses the standard family mechanism (sync-length signature measured on track 38, sent to the C64, used as a single repeating-byte XOR decryption key). For Hollywood Collection's live tracing and static disk analysis both found no functioning protection check at all in any locally-archived copy.

Having a genuine, actively-protected Ghostbusters II source (GhostbustersII_zrx_s0.g64, measured key $18) and Hollywood Collection's Disk 4 side by side made it possible to find not just that the protection was removed, but the exact two-instruction patch that removed it.

Summary

  • The genuine disk's directory is deliberately near-empty and obfuscated (as, gm1, side flag only, BAM reporting 0 blocks free) — the standard GMA-family convention. Hollywood Collection's Disk 4 directory is completely ordinary and legible, with individually-named game asset files and one conspicuous extra entry, gmaread.src.mod.
  • gm1.prg is 4 bytes shorter than the genuine version (1440 vs. 1444 bytes) and otherwise byte-for-byte identical apart from address shifts caused by two edits.
  • Edit 1: the JSR $C800 instruction (the fixed drive-upload-and-execute trigger used throughout the whole GMA family) is deleted outright — not bypassed, not patched to skip on a flag, simply removed. The drive never seeks to track 38 at all.
  • Edit 2: a single opcode byte inside the decrypt loop — EOR $D000,Y ($59) changed to LDA $D000,Y ($B9) — turns the XOR-decrypt pass into a harmless no-op self-copy.
  • The disk's own game data was correspondingly re-saved as already-decrypted plaintext, matching the now-legible directory.
  • gmaread.src.mod is an inert leftover file (bogus $FFFF load address, never actually loaded) containing recognizable fragments of the removed drive-upload routine — almost certainly the cracker's own extracted copy of the code they cut out.

Directory comparison

Genuine Ghostbusters II source (protection active): 

0 "gbii            "
0    "as"               prg
0    "gm1"              prg
1    "side flag"        prg
0 blocks free.

Hollywood Collection, Disk 4 (protection removed): 

0 "gbii            " pj 2a
1    "as"               prg
2    "gmaread.src.mod"  prg
6    "gm1"              prg
4    "mask2"            prg
4    "mask1"            prg
24   "vigosm image"     prg
24   "janosz image"     prg
24   "venkdana image"   prg
5    "vii text"         prg
4    "win text"         prg
14   "music b"          prg
1    "side flag"        prg
17   "music a"          prg
9    "gbiichars"        prg
121  "vigo 0800-8000"   prg
81   "vigo 8000-cfff"   prg
5    "vigo fc00-ffff"   prg
5    "gm2"              prg
313 blocks free.

The genuine disk's near-empty, obfuscated directory (real content hidden outside the normal directory chain, BAM deliberately reporting the disk as full) is the standard GMA-family convention documented throughout this project. Hollywood Collection's directory is a completely ordinary, legible file listing — the game's graphics, music, and code blocks are all individually named and directly loadable, consistent with data that no longer needs a decrypt step at load time.

Edit 1: the upload trigger is deleted, not bypassed

;; ---- genuine (protection active) ----
L03A6:  BNE L03A6
        LDA #$37
        STA $01
        LDA #$00
        JSR sub_0461         ; load file 0
        JSR $C800             ; <=== upload + execute the drive-side
                               ;      signature check, collect measured
                               ;      key byte in A
        PHA                   ; stash the REAL measured key
        LDA #$01
        JSR sub_0461          ; load file 1
        ...

;; ---- Hollywood Collection Disk 4 (patched) ----
L03A6:  BNE L03A6
        LDA #$37
        STA $01
        LDA #$00
        JSR sub_045E          ; load file 0 (same routine, renamed by the
                               ;   disassembler only because addresses shifted)
        PHA                   ; <=== stashes whatever A happened to hold
                               ;      after the LOAD call - NOT a measured
                               ;      key. The entire "JSR $C800" instruction
                               ;      (bytes 20 00 C8) is simply gone.
        LDA #$01
        JSR sub_045E           ; load file 1
        ...

Confirmed at the raw byte level: searching the genuine file for 20 00 C8 (JSR $C800) finds it at file offset 127; the identical search against Hollywood Collection's gm1.prg finds nothing anywhere in the file. The 3-byte call was cut out entirely, not disabled by a patched branch or a flag check — the loader's control flow simply never reaches the drive-side code at all.

Edit 2: a single-byte opcode patch neutralizes the decrypt loop

Even though nothing meaningful reaches it after Edit 1, the decrypt loop still runs — over whatever garbage value the removed JSR $C800 would otherwise have replaced with a real key: 

;; ---- genuine ----
        TXA
        EOR $D000,Y     ; 8A 59 00 D0  - actual XOR decrypt against the
        STA $D000,Y     ; 99 00 D0       key in X, byte by byte

;; ---- Hollywood Collection Disk 4 ----
        TXA
        LDA $D000,Y     ; 8A B9 00 D0  - reads the byte and immediately
        STA $D000,Y     ; 99 00 D0       overwrites A, discarding the
                          ;               "key" TXA just loaded - net
                          ;               effect: read byte, write the
                          ;               same byte back unchanged

One byte — $59 (EOR abs,Y) changed to $B9 (LDA abs,Y) — turns the entire decrypt pass into a no-op self-copy loop.

The leftover: gmaread.src.mod

A 374-byte file present only on Hollywood Collection's Disk 4, with a bogus $FFFF load address header — meaning nothing ever actually loads it; it just sits in the directory unused. Its content is unmistakably recognizable as fragments of the family's standard drive-side upload machinery: the M-W chunk-upload loop that builds a memory-write command byte by byte, and — near the end of the file — the exact LDA $1C00 / AND #$9F / STA $1C00 IEC-bus-initialization sequence that opens every drive-side program documented throughout this project's GMA-family investigations. This is almost certainly the cracker's own extracted copy of the code removed from gm1.prg in Edit 1 above — kept as a personal reference or backup rather than deleted, and an incidental second confirmation of the shared drive-side routine's own opening bytes for a title otherwise absent from every other cross-check in the GMA89 survey.

Conclusion

Hollywood Collection's Disk 4 is a clean, complete crack of Ghostbusters II's GMA89 protection — not an alternate build that never had one, and not evidence against anything documented elsewhere about the mechanism itself. The crack:

  1. Removes the drive-upload trigger, so the drive never seeks to track 38 at all (matching the D64-conversion and live-boot results that first flagged this disk as having no functioning check).
  2. Neutralizes the decrypt loop as a defense-in-depth measure, even though by that point it's only ever fed garbage.
  3. Replaces the on-disk data with its already-decrypted plaintext, matching the disk's now-ordinary, legible directory.

Ghostbusters II's own dedicated GMA89 sources remain the correct place to find this game's actual measured key ($18); Hollywood Collection's Disk 4 is documented here specifically as a case study in what a complete GMA-family crack looks like at the byte level, not as a fourth source for the key.

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