Lunar Eternal Blue (JP) doesn't work

[Former user]

Original issue 323 created by libretro on 2013-02-02T02:02:57.000Z:

What steps will reproduce the problem?
1. Load any image of Lunar: Eternal Blue (here is the cuesheet used in this case - http://pastie.org/6002365)
2. When I start up the '.cue' file, it shows me the Japanese Mega CD screen. After pressing Start, it shows the audio CD screen.
3. I then press Start again with the cursor highlighting the 'CD-ROM' button. It shows a 'Sega copyright screen'. After that, nothing will show up and the game won't progress - screen stays black.

What is the expected output? What do you see instead?
Expected output should be the game running. What we see instead is a black screen after the Sega copyright screen.

What version of the emulator are you using (official, SVN revision,...)?
Latest SVN revision.

Please provide any additional information below (Emulator settings, Console
setting,...)

I'm trying to load the Mega CD game 'Lunar - Eternal Blue' with a CUE sheet that looks like this -

I'm curious what the issue here is. I've had another guy test a bunch of Japanese Mega CD games for me and so far everything works except for Lunar Eternal Blue. Is there something wrong with my libretro code in libretro.c?

According to a user on my forum -

http://forum.themaister.net/viewtopic.php?pid=1360#p1360 (it's the first issue he mentions in this post but it seems he wrongly misattributed it to the libretro port).

According to him, the Japanese version of Lunar: Eternal Blue used to work, but not anymore. He initially thought that it was libretro's fault - but it turns out it affects the Wii version of Genesis Plus GX too.

[Former user]

Comment # 1 originally posted by ekeeke31 on 2013-02-02T09:11:29.000Z:

it's already fixed in r758, it was a regression introduced in r757, which was done after the official 1.7.3 release, hence why your user said it worked fine in the stand-alone version

As a technical reminder, when i fixed read-only registers on MAIN-CPU side in r757, I forgot about PRG-RAM write-protection register, which was then never set anymore. It appears this game accidentally tries to access the write-protected area, which ended up corrupting the SUB-CPU side code in RAM and later cause an exception.

[Former user]

Comment # 2 originally posted by libretro on 2013-02-03T20:54:41.000Z:

Thanks ekeeke.

BTW - as you can tell from the countless mails you've probably received from that nintygaming guy - people are not satisfied with how RetroArch GX currently looks like, and me and ToadKing are seriously not sure whether we are even doing things right in that regard anymore.

Could you go over the RetroArch GX port and possibly look at gx_video.c and tell us if/what we are doing wrong? I also heard from a guy that setting the resolutions the way we do on GX caused adverse performance in HBC and even the Wii Menu - so this has left me feeling very worried about the entire thing.

I would feel much more comfortable if somebody experienced like you could take a good look at it and help me out there in that regard.