[SLES_548.38] Donkey Xote black screen with ATA HDD

[azu-pl]

Game don't start with exFAT ata HDD. I tried every compatibility mode and some combinations but game only shows a black screen.

[rickgaiser]

I will test this when I get the chance.

[10522]

Donkey Xote [SLES_548.38]:

OPLNEUTV41 + Neutrino 20241019 USB - black screen on startup
OPLNEUTV41 + Neutrino 20241019 + udpbd-vexfat 0.2.0 - black screen on startup

OPL Beta 1.2.0 2156 USB ISO - works well
OPL Beta 1.2.0 2156 SMB ISO (Mode 6) - works well

My PS2 model is SCPH-90008. Compatibility modes do not help. I use redump images and don't use PADEMU, VMC, GSM.

[10522]

@rickgaiser

How is it possible that this game doesn't work in Neutrino but works in OPL? Also can you please check this and this Neutrino issues.

[rickgaiser]

How is it possible that this game doesn't work in Neutrino but works in OPL?

Good question. Neutrino should have at least OPL compatibility, so this is a bug I'll be investigating for sure.

[rickgaiser]

After some more investigation this game seems a problematic one to run, but also not much (or old) into available:

• ESR not working link
• Free HDLoader not working link
• OPL 0.9.3 needing mode "32" link

Other than that I could not find any info on this game. I tried OPL 2156 USB and indeed that boots the game, even without any compatibility mode.

Testing neutrino versions I can get this game to boot using version 1.0 from USB. I can also get this game to boot on the latest neutrino by reverting c53eeb4, AND enabling debugging on the fakemod iop module. So this makes me think this game is somehow sensitive to where it is loaded in IOP RAM, or where the emulation modules are loaded into IOP RAM.

No solution so far, but at least a direction to look into.

[rickgaiser]

I found the root cause of the issue with this game: a bug in the game itself!

The game allocates a 73984 byte buffer that overflows by 32 bytes. Depending on what is on that location this will cause random issues or no issues at all. The 32 bytes are overridden with zeroes, not even data.

The faulty module seems to be RTFSSIOP.IRX, but I cannot be 100% sure this module is the one making the allocation and the overflow, I only see this buffer being allocated directly after that module is loaded, so I assume it's that one, plus it's a custom module from the game studio.

If this module is used by other games as well they may suffer the same random issues. So if anyone knows how to track tris module in other games that would be very helpfull.

Working on a fix/workaround

[rickgaiser]

Fixed in the latest version by enabling compatibility mode '7'. -gc=7