TONS of zelda hacking
i used to do a lot of work with Ocarina of Time. fun fact: before blocklands maps died, i was working on importing levels from zelda into blockland. i had a lot of sucessful imports, like ganons tower, the entirety of the forest temple, and even hyrule field i all got loaded into blockland. unfortunately they were riddled with texture/collision errors, and i never could get them completely ironed out before blockland updated
other than that ive made lots of custom maps for zelda. ive also imported other levels from other games into zelda (super smash brothers stages, wind waker islands, animal crossing towns etc). my latest zelda project has been me trying to replace ganon from the final battle with toby, so that me and toby can have an intense and mighty stand off. i got his model into the game and he even loads as ganon properly, but somethings causing the game to crash. adding toby to ganons hierarchy as a new offset adds new bytes of data to zeldas offset table. if the offset tables size isn't equal to what it was calculated to originally, the n64 enters some kind of infinite graphics loop that causes the game to freeze. im almost positive the roms CRC needs to be recalculated but i have no clue how to make that happen lol
does that count as hacking? it feels more like regular modding once you get the hang of the basic tools, but most of your changes still come from either editing individual bytes of data with a hex editor or writing new ASM/C scripts from scratch