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Comment by steponlego | Hacker News Reader

Back in the '80s there was a lot of save game file hacking going on. My buddy and I would look at save game files for all the hot fun games in the hex editor and try to figure out what values we could change. Bard's Tale had a fairly simple layout, which we painstakingly figured out by, for example, using one item and seeing which values decremented. BTII or III, can't remember, went to some length to prevent this easy hacking of the save state. By the 1990s it was common for save game files to be obfuscated in various ways, making the process much more of a pain in the ass.

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Yeah I definitely agree, wasting time figuring out how to get to the save and apply your changes is the worst obstacle there, in most cases the saves are encrypted and have a check sum applied. Although I've found some games that allow you access the save data without messing around with this stuff, mainly the Shin Megami Tensei line of JRPG games in my experience.

Granted, the saves are binary blobs but once you find the value you want you can find an entire struct of data along side it. There are tools like imHex which help the process and help you define the structure of the save file. It's become a common project of mine to save hack and then build a save editor when I'm confident my changes work.

These days it's far easier to read/edit the memory of running programs than the serialized data saved to disk in save files.

Well; isn’t that why a lot of traditional ROM hacks historically (at least in the SEGA Genesis/MD hacking scene I was involved with) used savestates as rudimentary ROM hacks? EG - hasn’t it been easier to manipulate data in runtime memory, eg in a savestate; than within the ROM?

Asking because I don’t actually know, I’m just recalling a lot of my early ROM hacking, and indeed discoveries in ROMs, by manipulating memory and savestate rather than the ROM itself.

I couldn't tell you without a specific example, but I would suspect distributing an edited ROM would be much easier than save state hacking.

In a general sense, I suspect the latter is more popular because it's not illegal to modify/distribute save state data; ROMs certainly can be.

They distribute delta binary patches on the form of IPS formats.

Which gives me even less reason for why they would distribute modified ephemeral data vs source data to alter game logic.

Obviously, if you want all 151 Pokemon captured, you would do that through a save state. But if you want increased chances of capturing Pidgey, it would certainly be easier to distribute a ROM (or delte, in this case) with those new ratios baked in.

Savestate hacking used to be easier because everything in a savestate is uncompressed and raw. Tile graphics, level layouts, palettes, sprite mappings, etc.

To hack a ROM you need to know how to decompress the data, and then recompress your changes. A given game might use multiple compression formats.

We used to break into the monitor for research sometimes too. Great times, no real OS in the way either.

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