I adapted bytecode hack for Monkey Island II from Amiga crack to PC (data file) and it worked in earlier versions of SCUMMVM where protection was not removed.
FYI the newest versions of SCUMMVM now remove all protections from games (AlexH said so so it must be true)
The idea is: check a hack existing for Amiga (example: in the WHDLoad slave sources or Amigapatchlist), look the offsets around in an hex editor, and try to find the same bytecode in the PC version of the file. It worked for MI2 so why not the others...
PS: I have cracked most of ScummVM & Sierra games without knowing the byte code, but by hacking the executable & using "replay" technique at the correct moment.
I remember fondly cracking Operation Stealth on amiga in 1993 or 1994: took me 10 hours with Action Replay, and now when I look at my crack I don't even remember how I did it (but it still works flawlessly)!!