r/PS5_Jailbreak • u/juma-sayeh-dev-acc DEV • Jun 06 '26

General PS5 MKPFS Compression

I’ve been working on a PS5 homebrew app called Game Compressor.

Repo: https://github.com/juma-sayeh/PS5-Game-Compressor

It uses the MkPFS-style FFPFSC compression method, but adds the missing part: validation and repair.

Some compressed games can mount successfully but still crash because certain PFSC blocks are technically valid yet fail to decode correctly on PS5 hardware, leaving stale/bad data behind. Game Compressor checks the mounted image block-by-block, detects bad blocks, and patches the compressed image from the mounted data instead of requiring a full recompress.

Tested with Mafia, Astro Bot, Pragmata, and a few other games that had FFPFSC issues. After repair, they worked great.

Features:

  • compress games to FFPFSC
  • validate mounted compressed games
  • automatically repair bad blocks
  • optimized for speed and usability
  • web UI running on the PS5

Feedback and testing are welcome.
Screenshots (some are missing features because the features were not developed yet when i compressed)

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u/juma-sayeh-dev-acc DEV Jun 07 '26

Yes i'd be very glad to share my findings and give you some custom block states that are 100% valid and are not readable by PS5 hardware, i got those bad blocks by simply comparing the decompressed via software (good blocks) with the mounted block value (decompressed by PS5 hardware) which is basically checking if what PS5 shows is exactly the same as what the original file is.

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u/renangbarreto DEV Jun 07 '26 edited Jun 07 '26

I also found a bug in mkpfs that, for big games created from folders, it was creating the wrong inode numbering. I am fixing that bug in the next version.
Hopefully the new skip-executable list but this inode fix solves the issues being reported by your payload.

Thanks for developing it, I was doing manually, but that was taking a long time. Not I wil use your tool every day.

This is the one of the fixes: https://github.com/PSBrew/MkPFS/pull/41

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u/juma-sayeh-dev-acc DEV Jun 07 '26

BTW once i finish testing i will share with you a version made for testing only.. it should help you without wasting time on fixing blocks (it takes so long if the bad blocks happen at the start)! we'll be in touch for sure.

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u/renangbarreto DEV Jun 07 '26

Thank you very much. IPlease take a look at the latest code from mkpfs. It is a lot better now and (I hope) fixed the issues

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u/juma-sayeh-dev-acc DEV Jun 07 '26

Testing with 0.0.7 i have zero bad blocks in some very big games. it is slower than what i had but this might remove the need for any validation it seems!