Criteria for "trusted" dump

General No-Intro related discussions.
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yo1dog
Posts: 5
Joined: 06 Jun 2022 19:43

Criteria for "trusted" dump

Post by yo1dog »

I was surprised after dumping my GBA games and using clrmamepro with "Nintendo - Game Boy Advance (20220604-044441).dat" to rebuild, there were two unmatched games: The GBA NES Classic Series Zelda games. I found listings for both when searching DAT-o-MATIC for the MD5, but both are listed as "Not verified": https://datomatic.no-intro.org/index.ph ... =23&n=1492

Wiki states the "verified" status requires two "trusted" dumps. I'm curious: What constitutes a "trusted" dump?

I summited mine. Hopefully it helps!
Hiccup
Datter
Posts: 1559
Joined: 09 Oct 2015 11:29

Re: Criteria for "trusted" dump

Post by Hiccup »

A trusted dump is basically a dump with a clear source. A non-trusted dump (called "third party" in the database is) one that is distributed via p2p sharing or warez scene releases, i.e. one with no clear source. The definitions are a bit loose but that's basically it. Regarding NES Classic in particular, some of those entries need to be corrected in regards to the ROM size, at some point I'm sure a datter will do that (me if I have time).
yo1dog
Posts: 5
Joined: 06 Jun 2022 19:43

Re: Criteria for "trusted" dump

Post by yo1dog »

Yea I noticed all the dumps differed from the existing trusted dump, including mine. Is that a padding thing? Don't know much about dumping.

What serves as the source of truth when comparing hashes? I.e. why is 1MB/6d49cabf a good dump while 4MB/68b1b7a8 is bad?
KingMike
Posts: 643
Joined: 22 Sep 2012 16:36

Re: Criteria for "trusted" dump

Post by KingMike »

The "8" after the MX23L on the chip specifies it is an 8 megabit (1 MB) chip.
yo1dog
Posts: 5
Joined: 06 Jun 2022 19:43

Re: Criteria for "trusted" dump

Post by yo1dog »

KingMike wrote: 07 Jun 2022 18:02 The "8" after the MX23L on the chip specifies it is an 8 megabit (1 MB) chip.
Ah that makes sense. Though I don't see "MX23L" anywhere on the PCB nor in the header dump.

Also, where does the other 3MB come from?

I find all this very Interesting. Thanks!
KingMike
Posts: 643
Joined: 22 Sep 2012 16:36

Re: Criteria for "trusted" dump

Post by KingMike »

MX23L8... should be part of the text printed on the ROM chip on the PCB.

I haven't looked at the data specifically for those games.
I've only heard they do repeat data (aka "mirroring" on other consoles, where dumping certain address ranges gives a duplicate of data found at another range) which is said to be somehow partly used for the copy-protection which protects them from being run on most emulators (and was probably also put in by Nintendo to prevent third-parties from using their emulator without licensing).

But I do know that generally GBA games just read FF when read beyond the used data.
I've used a Retrode to dump mine. The firmware version I've used to dump them at least, could not detect the proper ROM size so it just defaulted to 8MB (which I since set it up to just always dump the maximum 32MB, then I would later use a hex editor to look at where the valid data ends. That is, if it should be trimmed to a 4, 8 or 16 MB ROM). I think the Famicom Mini/NES Classic games are the only official GBA games under 4MB.

The only Famicom Mini games I have are two from the final wave (of FDS-based games) which are among the few that ARE properly 4MB (seen by a "32" on the ROM chip).
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