Through the power of writing 15000 lines of fully commented assembly, I have created a ROM containing 125 accuracy tests, which you can find here:https://git...
Earthbound is notoriously difficult to emulate accurately, because the cartridge had a unique chip on it used to detect if the code was running on an authentic cart, for piracy detection. The game will run a check on this chip to read its voltage; if it’s not at the correct reading or if it returns a null value, the game would know it was running on a bootleg cartridge.
What it did then was kinda sinister. It didn’t stop you from playing the game. But it GREATLY increased the spawn rate of enemies, making the game significantly harder. Then, if you managed to make it through the antipiracy hard mode and get all the way to the final boss, the game would intentionally crash itself as soon as the battle begins, and it deleted your save file. You couldn’t finish the game. It let you get 99.99% of the way there, uphill, and then says “get bent” and wipes all your progress.
Those checks were designed to beat cartridge copiers, not emulators. Even the most inaccurate emulators from back in the day didn’t set off those checks.
There was no special chip on the cartridge either, not sure where you heard that from. What it did was check that the console is the correct region, that SRAM is the correct size (8kb, copiers would have more but emulators would get it right), and then checksum parts of the ROM to confirm it wasn’t tampered with.
There was no special chip on the cartridge either, not sure where you heard that from.
Hmm, I may be conflating or misremembering some details, possibly involving the Earthbound Zero prototype cartridges that were floating around for a while. It’s been a long time, but I do distinctly remember that very early in SNES emulation on PC, that there was a bit of a struggle getting Earthbound (Mother 3) to pass the piracy checks, though every emulator for the last ~20 years handles it just fine now.
It may have been a different Nintendo console that did a voltage check. But I’m pretty sure I didn’t just make that up out of nowhere. Now it’s gonna drive me crazy figuring out what I’m trying to remember. :(
TCRF has the exact implementation documented. One thing that’s commonly missed in the urban legends that get passed around about the game is that the two hardware checks prevent the game from running at all. It’s only the ROM checksums to see if those routines were tampered with that will then trigger hard mode. The point of that is to trick anyone trying to crack the ROM who might think they succeeded if they got their modified ROM to boot on a cartridge copier.
But this does mean that unless you modify the ROM, no emulator will ever trigger hard mode, an unmodified ROM will either run or it won’t.
Earthbound is notoriously difficult to emulate accurately, because the cartridge had a unique chip on it used to detect if the code was running on an authentic cart, for piracy detection. The game will run a check on this chip to read its voltage; if it’s not at the correct reading or if it returns a null value, the game would know it was running on a bootleg cartridge.
What it did then was kinda sinister. It didn’t stop you from playing the game. But it GREATLY increased the spawn rate of enemies, making the game significantly harder. Then, if you managed to make it through the antipiracy hard mode and get all the way to the final boss, the game would intentionally crash itself as soon as the battle begins, and it deleted your save file. You couldn’t finish the game. It let you get 99.99% of the way there, uphill, and then says “get bent” and wipes all your progress.
Those checks were designed to beat cartridge copiers, not emulators. Even the most inaccurate emulators from back in the day didn’t set off those checks.
There was no special chip on the cartridge either, not sure where you heard that from. What it did was check that the console is the correct region, that SRAM is the correct size (8kb, copiers would have more but emulators would get it right), and then checksum parts of the ROM to confirm it wasn’t tampered with.
Hmm, I may be conflating or misremembering some details, possibly involving the Earthbound Zero prototype cartridges that were floating around for a while. It’s been a long time, but I do distinctly remember that very early in SNES emulation on PC, that there was a bit of a struggle getting Earthbound (Mother 3) to pass the piracy checks, though every emulator for the last ~20 years handles it just fine now.
It may have been a different Nintendo console that did a voltage check. But I’m pretty sure I didn’t just make that up out of nowhere. Now it’s gonna drive me crazy figuring out what I’m trying to remember. :(
TCRF has the exact implementation documented. One thing that’s commonly missed in the urban legends that get passed around about the game is that the two hardware checks prevent the game from running at all. It’s only the ROM checksums to see if those routines were tampered with that will then trigger hard mode. The point of that is to trick anyone trying to crack the ROM who might think they succeeded if they got their modified ROM to boot on a cartridge copier.
But this does mean that unless you modify the ROM, no emulator will ever trigger hard mode, an unmodified ROM will either run or it won’t.
But that doesn’t happen on NSO, does it?