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We have two dumps of Beavis and Butt-Head available:

1. GG 3858f14f Beavis and Butt-Head (MTV's)
2. GG a6bf865e Beavis and Butt-Head (MTV's)

Until now, dump 3858f14f was labelled "US" and dump a6bf865e was labelled "Europe". This was because I could only dump the European version and I assumed the other dump, already available on the net was US. I now got access to a US cartridge and got a a6bf865e dump.

So the situation became:
a6bf865e - EU & US cartridges confirmed
3858f14f - Unknown dump source

We will assume the other dump is correct (and it has enough change) for now but I need to label way in a way to mark their ordering.
Can somebody help with reverse engineering the differences and figure out which of the two dumps came first, and possibly what are their difference?

There is a difference between game options:

Option menu:

a6bf865e
Remarks more/less

3858f14f
Speech on/off

There are a large number of differences between these ROMs. They include (where "Confirmed" is the dump with CRC32 a6bf865e, and "Unknown" is that with CRC32 3858f14f):

Playing the game shows at least one feature of "Confirmed" is missing in "Unknown": the latter lacks the ability to switch characters on the pause screen.
Examining disassembly shows that there are further features of "Confirmed" which are missing in "Unknown". For example: the function at $2cca in "Confirmed", which displays the message "Sorry boys, no tickets, no show!" (to explain why it is not possible to progress beyond a certain point in the game without a certain item), is completely absent from "Unknown".

I think the missing features make it clear that "Unknown" is an older version of the game than "Confirmed".

However, there are many more differences between the ROMs. They include:

"Unknown" sets the mapper control register at $fffc to $80, enabling "ROM write". "Confirmed" uses the expected value of $00.
"Unknown" contains some dead data including, interestingly, several paths of the form "c:\ahm\bandb\src\...". Presumably "ahm" is "Andrew H. Marrinson" - listed under both "Programming" and "Sound" in the credits.
Speaking of the credits, "Unknown" contains only the programmers, animators etc. "Confirmed" seems much more polished - it includes a large number of "Creative Consultants" and similar.

The sheer number of differences (even accounting for identical data in altered locations, fully 28% of the bytes are different), and the three above in particular, make me think that unless a released copy of "Unknown" is found, we should consider the possibility that "Unknown" is actually a prototype.

Paul Baker wrote

we should consider the possibility that "Unknown" is actually a prototype.

I'd say it looks extremely likely that it is a prototype.

I renamed this to prototype based on the info above.

I would add the fact that this sort of "short-marketting-burst" game release it extremely unlikely to have had an update and reprint like some of the more evergreen classic titles may have.

Author	Message
Bock Site Admin Joined: 08 Jul 2001 Posts: 8653 Location: Paris, France	Reverse Engineering Challenge : Beavis and Butt-Head (GG) variations Posted: Sat Oct 16, 2010 8:32 am
	We have two dumps of Beavis and Butt-Head available: 1. GG 3858f14f Beavis and Butt-Head (MTV's) 2. GG a6bf865e Beavis and Butt-Head (MTV's) Until now, dump 3858f14f was labelled "US" and dump a6bf865e was labelled "Europe". This was because I could only dump the European version and I assumed the other dump, already available on the net was US. I now got access to a US cartridge and got a a6bf865e dump. So the situation became: a6bf865e - EU & US cartridges confirmed 3858f14f - Unknown dump source We will assume the other dump is correct (and it has enough change) for now but I need to label way in a way to mark their ordering. Can somebody help with reverse engineering the differences and figure out which of the two dumps came first, and possibly what are their difference?

BFC Joined: 05 May 2007 Posts: 40	Posted: Sun Oct 31, 2010 2:32 pm
BFC Joined: 05 May 2007 Posts: 40	There is a difference between game options: Option menu: a6bf865e Remarks more/less 3858f14f Speech on/off

RetroSpark Joined: 08 Dec 2005 Posts: 488 Location: Melbourne, Australia	Posted: Fri Jan 07, 2011 11:16 am
	There are a large number of differences between these ROMs. They include (where "Confirmed" is the dump with CRC32 a6bf865e, and "Unknown" is that with CRC32 3858f14f): Playing the game shows at least one feature of "Confirmed" is missing in "Unknown": the latter lacks the ability to switch characters on the pause screen. Examining disassembly shows that there are further features of "Confirmed" which are missing in "Unknown". For example: the function at $2cca in "Confirmed", which displays the message "Sorry boys, no tickets, no show!" (to explain why it is not possible to progress beyond a certain point in the game without a certain item), is completely absent from "Unknown". I think the missing features make it clear that "Unknown" is an older version of the game than "Confirmed". However, there are many more differences between the ROMs. They include: "Unknown" sets the mapper control register at $fffc to $80, enabling "ROM write". "Confirmed" uses the expected value of $00. "Unknown" contains some dead data including, interestingly, several paths of the form "c:\ahm\bandb\src\...". Presumably "ahm" is "Andrew H. Marrinson" - listed under both "Programming" and "Sound" in the credits. Speaking of the credits, "Unknown" contains only the programmers, animators etc. "Confirmed" seems much more polished - it includes a large number of "Creative Consultants" and similar. The sheer number of differences (even accounting for identical data in altered locations, fully 28% of the bytes are different), and the three above in particular, make me think that unless a released copy of "Unknown" is found, we should consider the possibility that "Unknown" is actually a prototype.

Maxim Site Admin Joined: 19 Oct 1999 Posts: 14745 Location: London	Posted: Fri Jan 07, 2011 12:15 pm
	Paul Baker wrote we should consider the possibility that "Unknown" is actually a prototype. I'd say it looks extremely likely that it is a prototype.

Bock Site Admin Joined: 08 Jul 2001 Posts: 8653 Location: Paris, France	Posted: Thu Oct 02, 2014 12:24 pm
	I renamed this to prototype based on the info above. I would add the fact that this sort of "short-marketting-burst" game release it extremely unlikely to have had an update and reprint like some of the more evergreen classic titles may have.

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