1942 ROM ERROR ! CHECK AGAIN !

[mandoju]

Hi,
I tryed to finish this loved game 1942, the game crash random after "last 25 stage", i tryed another sets of the ROMs, i tryed a all clones versions, without cheats. I use the last Mame version mame0267b_64bit.exe. I made test with ancient vesions and the problemm is the same. I tryed in another PC, the issue is the same.

ROM ERROR ! CHECK AGAIN !
@ 1984 CAPCOM

1942 (Revision B) [1942]

Please help-me to remember great days of the my past...

Jorge - Rio de Janeiro Brazil

[mandoju]

I found the problemm, i think, the apparent inocent cheat code "Select Shot Speed", causes de bug! I maked test using only cheat option "Rapid Fire". And the bug goes out .. The "Select Shot Speed" cheat option should will be with a warning.
Thank for all.

Jorge Rio de Janeiro Brazil.

[mandoju]

Same problemm, problemm with only cheat "Rapid Fire" , i quit...

[mhoes]

Hi,
I tryed to finish this loved game 1942, the game crash random after "last 25 stage", i tryed another sets of the ROMs, i tryed a all clones versions, without cheats. I use the last Mame version mame0267b_64bit.exe. I made test with ancient vesions and the problemm is the same. I tryed in another PC, the issue is the same.

ROM ERROR ! CHECK AGAIN !
@ 1984 CAPCOM

1942 (Revision B) [1942]

Please help-me to remember great days of the my past...

Jorge - Rio de Janeiro Brazil

I found the problemm, i think, the apparent inocent cheat code "Select Shot Speed", causes de bug! I maked test using only cheat option "Rapid Fire". And the bug goes out .. The "Select Shot Speed" cheat option should will be with a warning.
Thank for all.

Jorge Rio de Janeiro Brazil.

Same problemm, problemm with only cheat "Rapid Fire" , i quit...

Although I cannot find the relevant information right now, I do seem to remember that enabling the 'cheat system' in MAME in any way will result in modifying the game in ways that will result in 'undefined behavior', because it changes it from what the original code was supposed to do.

In that sense, enabling any/all MAME cheats definitely come with a warning.

Can you see if you can reproduce the issue with the entire cheat system disabled ?

[mandoju]

I made tests with clone 1942 (Tecfi PCB, bootleg?) ROM 1942p, with cheats codes "Select Shot Speed" and "Rapid Fire".
The game works fine all 32 stages, i ended the game .
Anibody have a ideia of the problemm with "oficial" game, bug?

[mhoes]

I made tests with clone 1942 (Tecfi PCB, bootleg?) ROM 1942p, with cheats codes "Select Shot Speed" and "Rapid Fire".
The game works fine all 32 stages, i ended the game .
Anibody have a ideia of the problemm with "oficial" game, bug?

Can you see if you can reproduce the issue with the entire cheat system disabled ?

Additionally - when you have all cheats and the cheat plugin disabled - make a 'savestate' right before the error occurs, so people can perhaps troubleshoot the issue. Thanks.

[mandoju]

Hi,
I made test with without any "cheats" codes the bugs no appears, but this game without codes is very annoying game

[mhoes]

Hi,
I made test with without any "cheats" codes the bugs no appears, but this game without codes is very annoying game

Then it appears to be a problem with the cheats, and not with MAME. Do you remember where you got the cheats ? You could try to get the cheats fixed over there.

[mandoju]

I found the solucution in Pugsy forum.

https://www.mamecheat.co.uk/forums/viewtopic.php?t=5568

Original poster misunderstand. It's not any BUGs. in-game ROM check routine detects that ROM is tampering by cheat system. So it's correct behavior.

Solution is simple, you don't use any ROM codes or disable in-game ROM check routine.
I post the codes based on the latter thinking.

1942.xml

<cheat desc="Skip In-game ROM Check">
<script state="on">
<action>temp0 = maincpu.mb@711A</action>
</script>
<script state="run">
<action>maincpu.mb@711A = 18</action>
</script>
<script state="off">
<action>maincpu.mb@711A = temp0</action>
</script>
</cheat>