Unpatching ISOs + ripping question

[stevealexanderames]

Yesterday i was putting some of my ISOs in the memory stick, and since i haven't got a lot of free space (12 GB out of 16 are made of psx games i can't live without ) i was wondering how i can make ISOs smaller. I usually use YACC with the CisoPlus option to compress (to erase the update and not compress the video/audio files), and i noticed that in the options i can even set the BOOT.BIN to the non-writing area.
SO, first question: what's the exact utility of the BOOT.BIN? Can i erase it from the ISO and still have a playable game?

Second question is just a curiosity: is it possible to unpatch a prometheus-patched game?

[TragicTheBlubbering]

You can re-dump the umd to get a fresh nonpatched back up. To shrink your ISOs for extra space you can convert them into CSOs which are compressed so they can be quite a bit smaller depending on the compression level, Isotool can also do this but a better alternative if you run Windows is UMDGen which is an ISO/CSO converter and editor with alot of features.

Edit: Oops I forgot to answer the first Question. IIRC you can safely delete the BOOT.BIN with no problems. EBOOT.BIN is what gets loaded. BOOT.BIN is just used to automatically boot the UMD when the UMD Auto Start option is enabled in settings if I'm not mistaken, so it's not needed to run the backups.

[stevealexanderames]

You can re-dump the umd to get a fresh nonpatched back up. To shrink your ISOs for extra space you can convert them into CSOs which are compressed so they can be quite a bit smaller depending on the compression level, Isotool can also do this but a better alternative if you run Windows is UMDGen which is an ISO/CSO converter and editor with alot of features.

Edit: Oops I forgot to answer the first Question. IIRC you can safely delete the BOOT.BIN with no problems. EBOOT.BIN is what gets loaded. BOOT.BIN is just used to automatically boot the UMD when the UMD Auto Start option is enabled in settings if I'm not mistaken, so it's not needed to run the backups.

thanks for the answer it's a very small file but i guess i'm deleting it from now on

and for the patch, of course you're right i was actually curious about what the patch process changes in the ISO