[NES] Was Probotector II Return of the Evil Forces verified?

General No-Intro related discussions.
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iniche
Posts: 4
Joined: 23 Jun 2014 02:41

[NES] Was Probotector II Return of the Evil Forces verified?

Post by iniche » 17 Dec 2015 19:16

There seem to be 2 different versions of the ROM available on the internet.

One, which is present in the No-Intro and Goodsets.
Another that I don't know which set it came from. There's no indication on the file name that it's bad, alternate, etc.

They differ in just one location, byte 06. I know that this is insignificant to the game's main data since it's just the header. But what could be the reason for this discrepancy?

einstein95
Datter
Posts: 108
Joined: 02 Nov 2014 08:37

Re: [NES] Was Probotector II Return of the Evil Forces verif

Post by einstein95 » 18 Dec 2015 10:37

iniche wrote:There seem to be 2 different versions of the ROM available on the internet.

One, which is present in the No-Intro and Goodsets.
Another that I don't know which set it came from. There's no indication on the file name that it's bad, alternate, etc.

They differ in just one location, byte 06. I know that this is insignificant to the game's main data since it's just the header. But what could be the reason for this discrepancy?
It depends as the iNES header is done on the binary level http://wiki.nesdev.com/w/index.php/INES#Flags_6
Most likely because of an incorrectly set mapper or something.

KingMike
Posts: 406
Joined: 22 Sep 2012 16:36

Re: [NES] Was Probotector II Return of the Evil Forces verif

Post by KingMike » 01 Jan 2016 21:05

No-Intro does not concern itself with the accuracy of emulation headers (from what I have read, ideally No-Intro would identify only headerless ROMs. But that's not feasible for NES emulation.)

Indeed probably bad header. I know I saw that problem myself when someone released a patch for Quest of Ki. I noticed two different ROMs that again only were different by the header. In that case, mirroring.
(since that game was identified as MMC3 even though it's actually a Namco variant. Nintendo MMC3 uses software mirroring which makes the header irrelevant but Namco's variation does not have software mirroring, so a bad header will cause graphics glitches in-game.)

einstein95
Datter
Posts: 108
Joined: 02 Nov 2014 08:37

Re: [NES] Was Probotector II Return of the Evil Forces verif

Post by einstein95 » 03 Jan 2016 15:52

KingMike wrote:No-Intro does not concern itself with the accuracy of emulation headers (from what I have read, ideally No-Intro would identify only headerless ROMs. But that's not feasible for NES emulation.)
That's what No-Intro does, afaik. The checksums are for the PRG+CHR part of the ROM. The header is skipped by ROM-checking software like clrmame pro by using the header skip file.

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