LancerDL
Posts: 2
Joined: Mon Dec 19, 2016 9:26 pm

ROM .keys sometimes needed in recent MAME builds

Tue Dec 20, 2016 6:26 am

After running mame64 0176 for a while, I recently updated to 0180 and noticed a few ROMs that used to work were now missing files. When using "mame64 -listroms <rom>" a new entry was present relative to 0176. Namely <rom>.key, where <rom> is the name of that particular <rom>.zip file.

This addition was not present with all ROMs, so my questions are:

1) What is it? It's only about 20 bytes.
2) Where does this requirement come from? Ie: What causes it to be needed in some ROMs and not others?
3) Does a new dump need to be done for the ROMs affected?

Thanks.

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B2K24
Posts: 44
Joined: Wed Mar 30, 2016 5:43 am

Re: ROM .keys sometimes needed in recent MAME builds

Tue Dec 20, 2016 4:39 pm

http://docs.mamedev.org/usingmame/aboutromsets.html

https://www.reddit.com/r/MAME/comments/ ... h=e9867996

There's also options of reading the whatsnew.txt as well as hooking mameinfo.dat into your front end which will display specific changes and information depending which set is highlighted.

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Tafoid
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Location: Vermont USA
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Re: ROM .keys sometimes needed in recent MAME builds

Tue Dec 20, 2016 5:02 pm

LancerDL wrote:After running mame64 0176 for a while, I recently updated to 0180 and noticed a few ROMs that used to work were now missing files. When using "mame64 -listroms <rom>" a new entry was present relative to 0176. Namely <rom>.key, where <rom> is the name of that particular <rom>.zip file.

This addition was not present with all ROMs, so my questions are:

1) What is it? It's only about 20 bytes.
2) Where does this requirement come from? Ie: What causes it to be needed in some ROMs and not others?
3) Does a new dump need to be done for the ROMs affected?

Thanks.
I have to assume you are referring to changes in the CPS2 driver and games such as (aka Street Fighter Alpha, Megaman 2, Marvel Vs. Capcom, etc)? This happened in http://mamedev.org/releases/whatsnew_0178.txt

Code: Select all

-cps2: Use keys that can be programmed onto a CPS2 motherboard [smf, Eduardo Cruz, Andreas Naive]
These added .key files represent what is needed for the actual CPS2 motherboard to allow it to be upgraded or fixed properly and also provide what is needed for emulation to decrypt on the fly to allow the games to work. The old internal method of decryption of CPS2 games did not allow this on real boards so games which were "suicided" (lost battery power) could not be fixed and had to be alternatively programmed and would not retain original code.

So, yes, from MAME 0.178 onwards, there are a key file required for all CPS2 romsets. I can't tell you how to get them but if you've found roms before, you should have no trouble finding updates.

LancerDL
Posts: 2
Joined: Mon Dec 19, 2016 9:26 pm

Re: ROM .keys sometimes needed in recent MAME builds

Tue Dec 20, 2016 11:11 pm

Thanks folks for your responses! The term "key" is used in a lot of the documents, so I wasn't sure which one applied in this particular case. Thanks also for pointing out the exact version; this is helpful. I see that this may affect other Capcom ROMs.

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