N64 GameShark ROM Reverse Engineering

[gudenau]

I am interesting in reverse engineering the ROM of the Nintendo 64 Gameshark, I have managed to find a tool that allows decryption of the ROM images.

Now I am trying to figure out how I could load the ROM image into some sort of disassembler. When looking at the ROM in a hex editor I found what seems almost like a 0x39C0. The strings appear later in the ROM.

The main thing I want to accomplish is the ability to access the parallel port in custom code, from what I have seen this has been done just not publicly documented.

Hashes:

  File: ar3.enc
CRC-32: 242eb6dd
   MD4: e31885d797d73579b61a80ecbc4b7aea
   MD5: e611755c131790cb79d961ca477de6d4
 SHA-1: c935652989a3445fe770133da03da8f9a8e69b57

  File: ar3.dec
CRC-32: c616a684
   MD4: 70bb729e61220c5d26f0afe8dae19ccc
   MD5: ea635ebc4f58481be60d6d532c232870
 SHA-1: d7b7ddf211c93bf4d5fca959f7e850fd5cda373d

 

[AriaHiro]

I'm not sure due to when I was a bit more active I dealt with the end result but The guy working on Mupen64plus AE has been fiddling with the game shark pro trying to get roms to dump on modern hardware. For his purpose, there are already superior tools but homebrew on the real thing sounds like a really interesting and cost effective use of hardware most people already have. I'm not sure if it will help in any way but here's his blog. http://www.paulscode.com/forum/index.php?topic=1773.0
Edit Sorta unrelated and this doesn't have the checksum data but people have already cracked the lockout chip. https://github.com/mikeryan/UltraCIC

 

[gudenau]

I'm not sure due to when I was a bit more active I dealt with the end result but The guy working on Mupen64plus AE has been fiddling with the game shark pro trying to get roms to dump on modern hardware. For his purpose, there are already superior tools but homebrew on the real thing sounds like a really interesting and cost effective use of hardware most people already have. I'm not sure if it will help in any way but here's his blog. http://www.paulscode.com/forum/index.php?topic=1773.0
Edit Sorta unrelated and this doesn't have the checksum data but people have already cracked the lockout chip. https://github.com/mikeryan/UltraCIC

Ahh, this could help getting started on the PC side of things. Thanks for pointing me to Paul's stuff, forgot he did N64 stuff.

 

[gudenau]

Gosh darn, I wanted to investigate this more and I can not find the tool I used to decrypt the ROM.