Can I fix a CORRUPT PlayStation 2 save file?

[soda.]

“Dad? That old computer beeped!”
“Oh, So it is finished.”
“What’s this?”
“It’s a checksum… that my ancestor wanted.”
“What checksum, dad?”
“Test drive unlimited”
edit:
".. what's Test drive unlimited?"
".. i don't know"

[jjb]

I love how he’s gotten to the point of resurrecting game consoles and now has surpassed that, and is now trying to bring back a save file. What comes after I don’t know and I’m interested to see.

[dkt]

It looks like those missing bytes were for the completion loading message.

at 0:19 it has: "Only one profile can be loaded per game session. You will need to reset the console..."

but when those bytes are missing at 16:19 the message stops at "You will"

the end of the string could be those missing bytes.

[SebastianLague]

I selfishly hope there are many more corrupted save files in your future! Was very entertaining to watch you puzzling this out :)

[EER]

To be fair, reverse engineering the game save format sound like much more fun than playing the same game again to 75%

[iClone]

I find it hilarious to imagine that those 9 bytes did actually mean something, and you have a random car that is missing a rear left wheel or something like that.

[Larry]

I remember completing The Great Escape on the PS2 and the save you get after finishing the game corrupted the entire memory card. Lost literally months of game work. >:(

[_notch]

Another major problem with brute forcing a the reverse of a 32 bit checksum with more than 32 bits of variable data is that at least some (all, if good algorithm) checksums will have multiple solutions due to the pigeon hole principle.

[user_romanport]

This reminds me of when I had to rescue my save file from the Spyro Reignited Trilogy on Steam. I too was going for an 100% save file and was nearly finished with the game, when while playing it suddenly froze while saving. I realized I had run out of disk space. Freeing up disk space didn't cause it to unfreeze, and I noticed it had already deleted the original file and started partially writing the updated save file. It was a zero byte file though, so there was no trace of it on the disk anymore.

I ended up freeing up space and doing a memory dump of the process and manually searched through the game's memory. I figured that the save file was still in a buffer somewhere in memory, and to my astonishment, that guess was correct. After searching for the game's file header in memory, I came across a large block of save-file-looking data. I copied it out of the process memory and into the save file. Killed the process, restarted the game, and crossed my fingers...and it worked!

As always, great video man!

[sadmac]

"And, yeah, somehow, this still seemed preferable to replaying the game from scratch." Now where have I seen that energy before

[DrewDoesThings]

You absolutely could've just replayed the game to get back to where you were before the save corrupted, but I believe there's much more value in this issue being motivating enough to drive you to make an entire video on it, giving your viewers extra entertainment and education that we would've missed out on had you given up or restarted. Thanks for that!

[xDeltaFx]

Even if the bruteforcing could complete in our lifetime, the fact that the number of possible combinations is bigger than the size of the checksum itself (4 bytes = ~4 billion) means that there are most likely an overwhelming number of possible combinations for those 11 bytes that would produce the same checksum, without any way of determining which combination was the original one.

[AbjectPermanence]

This was a really good one. Instead of centering on hardware like this channel usually does, this video is more about figuring out how to force software to do what you want. I really liked that.

[mazda]

Fun fact: I also lost all of my progress in Test Drive Unlimited once because I accidentally turned it off during one of the autosaves (it autosaves all the damn time). I had to start fresh and decided to turn off the setting just to be safe. Also, this game has full 16:9 widescreen support and it makes the game look much better. The only way to activate the setting is by actually setting the Playstation 2 itself to 16:9 in the main menu.

[cybersilver]

0:58 For future reference, you should try opening and closing the disc tray. I haven't had to try during a save, but it's unfrozen my games in the past without repercussions

[IcySon]

This was fantastic! As a fan translator for many a game and of course many game file formats, it's always a treat to watch others doing similar reverse engineering work. Awesome~

[gamechep]

Woah. It's like magic. Fun fact: when my PS2 broke, I had created a backup of save files just like you did, and when I tried to load the latest one in PCSX2, it said 'Data Corrupt' (Prince of Persia: Warrior Within), with a new logo (usually it would be the place and time where I'm at) Thankfully, I had backup saves.

[notbrandon]

Number Is [309, 485, 009, 821, 345, 068, 724, 781, 056 or 309 Septilion, 485 Sextillion, 9 Quintillion, 821 Quadrillion, 345 Trillion, 68 Billion, 724 Million, 781 Thousand 56] Number Location: 10:04

[ctre]

This man is becoming too powerful for his own good, and I'm loving watching it. I doubt I'll ever be *this* good at software, but it's still damn interesting. I'd love to know a bit about your background, where you learned everything you know and what got you into all of this.

[CookiePLMonster]

Was the FISH tag generated by the encryption function or some generic save routine? If it was the output of the encryption, then perhaps it's an indicator of the save using Blowfish for encryption?