Dolphin, the GameCube and Wii emulator - Forums

So I've been having some trouble with numerous games on Dolphin popping up with read and write errors. I'm pretty sure it's because I use shrunken ISOs (Shrunken using GCMutility), as I used to normally play games through Nintendon't on my Wii U, and Nintendon't never had any issues with these, so I shrunk all of them and deleted the 1:1s thinking I wouldn't need them. Now, I'm living far away from my original discs, and I've gotten a new laptop, so I wanted to switch over to using Dolphin. Well, many of my games, most notably Rayman 3, which as soon as I get past the language selection screen spams me with a seemingly endless supply of read and write errors, starting with "The disc could not be read (at 0x56ab0000 - 0x56ab6d28)." and numerous others after that with different numbers, eventually hitting "Invalid write to 0x00bcdeba, PC = 0x800c0308" where it just keeps showing the same error over and over every time I hit Ok, and I end up having to close Dolphin through the task manager. I do remember firing up the same ISO in dolphin for Rayman 3 before I shrunk it, and it worked without any issue. And this same exact shrunken ISO on my flash drive works perfectly in Nintendon't. I've played through to about halfway through the game without a single problem. Clearly, there's some kind of difference in handling of shrunken ISOs between Nintendon't and Dolphin, and I know numerous other games in my collection do this too at one point or another, though I can't remember any of the others at the moment. Normally I'd think this as no big deal, seeing as there's barely any space saved for Rayman 3 shrunken anyway, but my actual GC disks are about 2000 miles away right now, and I'd rather not have to rebuy games, not that I really can in the first place. Is there anything I can do here? Perhaps even some way Dolphin could integrate a similar system for handling shrunken ISOs? Or am I going to just have to wait a year or so until I can get my disks back and play the games through Nintendon't?

What is the exact size in bytes of the Rayman 3 ISO?

According to Windows, it's 1,454,075,148 bytes. 1,454,080,000 on disk, if that matters.

The shrinking program seems to have neglected to pad the data at the end to fill a DVD sector. Dolphin should be able to handle the ISO correctly if you add a little bit of padding data to the end of the ISO to make it larger (I suggest a size of 1,454,075,904 bytes, since that's a multiple of 2048, but smaller sizes might also work). You can do that using a hex editor. What the data is shouldn't really matter, but I would set it to zeroes.

Thank you, that seems to have done the trick! What should I do if I encounter this again? Just make sure the size in bytes is a multiple of 2048?

Yes, I would suggest padding any ISO that you run into this problem with. I'm not sure if 2048 actually is the number you need, but if it isn't, the number you actually need is probably smaller.