Author Topic: Street Fighter Alpha 2: Different Checksum upon every restart??  (Read 3313 times)

Offline Naudiz

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I'm having a weird issue with the US-Cartridge of Street Fighter Alpha 2. Maybe it has to do with its Special Chip? At first I noticed that Snes9x gives me a bad-checksum-warning (the game seems to run though). While retrying, I noticed that the checksum changes everytime the Retrode is reset. here are two Logs, that were made by simply pressing the reset-button, without touching the cartridge (check out the line "Actual Checksum"):

Code: [Select]
File: H:\StreetFighterAlpha2465.sfc
Name: STREET FIGHTER ALPHA22
Speed: 32/FastROM
ROM Map: LoROM
Type: 43
Kart contents: ROM+S-DD1
Header ROM Size: 32Mbits
Calculated ROM Size: 32 Mbits
SRAM size: 0Kbits (0Kbit)
Actual Checksum: 0B44
Header Checksum: DB9A
Header Checksum Compliment: 2465
Output: NTSC 60Hz
CRC32: 13A6EF7D
Licensee: Nintendo
ROM Version: 1.0
Region: USA/Canada
Code: [Select]
File: H:\StreetFighterAlpha2465.sfc
Name: STREET FIGHTER ALPHA22
Speed: 32/FastROM
ROM Map: LoROM
Type: 43
Kart contents: ROM+S-DD1
Header ROM Size: 32Mbits
Calculated ROM Size: 32 Mbits
SRAM size: 0Kbits (0Kbit)
Actual Checksum: A6A6
Header Checksum: DB9A
Header Checksum Compliment: 2465
Output: NTSC 60Hz
CRC32: 5910B7C8
Licensee: Nintendo
ROM Version: 1.0
Region: USA/Canada

I've tried it several more times and the checksum seems to change completely random every time. Isn't this weird?

Offline Matthias_H

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Re: Street Fighter Alpha 2: Different Checksum upon every restart??
« Reply #1 on: 30/Jun/2012 07:10:44 AM »
Not really all that weird. The S-DD1 chip keeps the Retrode from reading the majority of the ROM content. If some of its registers are not automatically reset upon restart, this sort of randomness can be expected.
https://www.retrode.org

I no longer sell the Retrode. For sales inquiries, please contact our friends at DragonBox.

Offline Naudiz

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Re: Street Fighter Alpha 2: Different Checksum upon every restart??
« Reply #2 on: 30/Jun/2012 01:38:14 PM »
OK thanks, I understand. So this sounds like an issue, which can't be resolved by future firmware-updates, right?