MkPFS.CSharp

Build, check and repair PS4/PS5 game images from the command line or a desktop app.

MkPFS.CSharp is a .NET 10 port of the Python MkPFS by PSBrew. It is a single native program (no Python needed), writes the same images as the original, and adds an offline PFSC block repair ported from PS5 Game Compressor and LZ4 asset packs for AMPR Emu.

Warning

AMPR packing (ampr, the AMPR Packs page) is experimental. It can shrink a game a lot, but whether the packed game runs depends on how that game reads its files, and only a test on the PS5 shows that. Keep the original game until the packed one has been played. See AMPR asset packs.

Warning

PS5 debug packages (pack fpkg, the Pack FPKG page) are experimental. They match the packages PS5PkgTool builds, but neither has been confirmed to install on a console yet. Fake packages only start games on firmware 11.60 and below (see Console compatibility). See PS5 debug packages.

Contents

• Features
• Quick start
• Console compatibility
• Download
• Desktop app
• Command line
• APR Emu
• AMPR asset packs
• PS5 debug packages
• Differences from Python MkPFS
• Build from source
• Credits and license

Features

	Feature	What it does
💿	exFAT images	Turns a game folder into an .exfat image (deterministic, 64 KiB clusters).
🗜️	FFPFSC images	Compresses an exFAT image, a game folder or any single file into a .ffpfsc (PFSC, zlib).
📁	Plain PFS	Packs a folder as a .ffpfs (--raw), signed, encrypted, 64-bit inodes or PS4.
📚	Batch	Packs every game folder and image in a folder in one run.
🔍	Check	verify, inspect, tree and unpack for PFS, PFSC and exFAT, encrypted ones too.
🩹	Repair	Finds and fixes compressed blocks the PS5 may decode wrongly (images made with ISA-L).
🎮	APR Emu	Copies AMPR Emu into a game's fakelib/ and writes its ampr_emu.index.
📦	AMPR packs (experimental)	Packs game data into LZ4 asset packs that AMPR Emu reads on the fly.
🧩	PS5 debug packages (experimental)	Builds a fake-signed .pkg from a game folder, as PS5PkgTool does, and reads .pkg files back.
🖥️	Desktop app	Every command in a window, in English, Português (BR), Español, Română, Deutsch and Français.

Quick start

ShadowMountPlus works best with an exFAT image wrapped in a compressed .ffpfsc. The desktop app follows the same two steps.

flowchart LR
    A["📁 Game folder<br/>PPSA12345-app"] -->|"1. Pack exFAT"| B["💿 PPSA12345.exfat"]
    B -->|"2. Pack FFPFSC"| C["🗜️ PPSA12345.ffpfsc"]
    C -->|"copy"| D["🎮 PS5<br/>ShadowMountPlus"]

Loading

mkpfs pack exfat PPSA12345-app PPSA12345.exfat     # 1. build the exFAT image
mkpfs pack file PPSA12345.exfat PPSA12345.ffpfsc   # 2. compress it
mkpfs verify PPSA12345.ffpfsc --source-file PPSA12345.exfat   # optional: check it

Which file should I make?

Output	Size	Made with	Use it for
.exfat	Same as the game	pack exfat	The input of pack file, or a mount without compression.
.ffpfsc	Smaller (zlib)	pack file, pack folder	The usual image for ShadowMountPlus.
.ffpfs	Same as the game	pack folder --raw	Signed, encrypted or PS4 images.
AMPR packs	Much smaller (LZ4)	ampr game	Experimental: AMPR titles with a tested profile.
.pkg	Smaller (Kraken)	pack fpkg	Experimental: a fake-signed debug package to install.

Console compatibility

What each output needs on a jailbroken PS5, and the firmware it works on. These limits come from the console-side tools and from reports of other tools' output, as of October 2026; MkPFS's own files have not been tested on every firmware.

Output	Runs with	Firmware	Notes
.pkg (pack fpkg)	kstuff-lite, package installer	Starts games on 11.60 and below	On 11.61, 12.xx and 13.xx the package installs but the game does not start.
.ffpfsc (pack folder, pack file)	ShadowMountPlus with kstuff-lite 1.07+	Up to 13.60	ShadowMountPlus lists PFS images as experimental.
.ffpfs (pack folder --raw)	ShadowMountPlus	Up to 13.60	Experimental in ShadowMountPlus.
.exfat (pack exfat)	ShadowMountPlus	Up to 13.60	The compatibility format.
AMPR packs (ampr)	AMPR Emu in fakelib/, through ShadowMountPlus	No published range; as ShadowMountPlus	Not verified.

• The current public jailbreak covers firmware 7.00 to 13.60 (PS5 and PS5 Pro); 14.00 and newer have none.
• The 11.60 limit of fake packages is in the console's kernel patches (kstuff), not in how a package is built. It is expected to rise with a later kstuff release.
• A game built for a newer firmware than the console's needs a backport, whatever the format; MkPFS does not backport games.

Download

Get the archive for your system from the releases page and unpack it anywhere.

System	Command line	Desktop app
Windows x64	mkpfs-<version>-win-x64.zip	mkpfs-gui-<version>-win-x64.zip
Linux x64	mkpfs-<version>-linux-x64.tar.gz	mkpfs-gui-<version>-linux-x64.tar.gz
macOS Apple silicon	mkpfs-<version>-osx-arm64.tar.gz	mkpfs-gui-<version>-osx-arm64.tar.gz

Tip

• Keep each program in its folder with the libraries next to it (mkpfs_zlib, plus Skia and HarfBuzz for the desktop app).
• macOS: the desktop app is MkPFS.CSharp.app. It is not notarized, so open it the first time with right-click > Open.
• Linux: the desktop app needs X11 and fontconfig, which desktop distributions include.
• SHA256SUMS.txt on the release page lists the checksums. mkpfs selftest checks the command line.

Desktop app

mkpfs-gui runs the same commands from a window and shows their output and progress.

Pack exFAT: game preview and APR Emu	Pack FFPFSC: compression tuning
AMPR Packs: build a playable packed game	Repair: block map of risky blocks

Section	Page	What it does
Build	Pack exFAT	Game folder → .exfat, with the APR Emu libraries and index.
	Pack FFPFSC	.exfat (or any file) → compressed .ffpfsc.
	AMPR Packs	Every ampr command; Build playable game is the default.
Check	Verify	Checks an image, optionally against its source.
	Repair	Scans an image, draws a block map and repairs risky blocks.
Read	Inspect, Tree, Unpack	Shows details, lists files and extracts an image.

• Game preview: pick a game folder or image to see its cover, title, IDs, version, region and APR Emu marker.
• Compression tuning: presets (Fast, Balanced, Max, Low RAM), the zlib level, block size and keep rules. CPU Cores offers Auto, which uses every physical core (not the logical processors), or any lower count.
• Tooltips: hover over any Compression Tuning or Advanced option to see what it does.
• One progress bar per run: a run with several steps (pack, then verify and compare) fills one bar, and the label names the step, for example verify (2/3).
• Safe closing: closing the window during a job asks first; Stop and Close waits for the job to clean up.
• pack folder and batch are available on the command line only.

From a source checkout: dotnet run --project src/MkPFS.Gui -c Release.

Command line

Paths may be absolute or relative. <...> is your value, [...] is optional, and mkpfs <command> --help shows every option.

Command	Result	Purpose
pack exfat <source_dir> [output]	<titleId>.exfat	Build an uncompressed exFAT image.
pack file <source_file> <image_file>	.ffpfsc	Compress one file (usually an .exfat) into a PFS image.
pack folder <source_dir> <image_file>	.ffpfsc	Wrap a folder in exFAT and compress it in one pass.
pack fpkg <source_dir> [output]	<content-id>-A<ver>-V0100.pkg	Build a fake-signed PS5 debug package (details).
batch <source_dir> <output_dir>	one .ffpfsc per item	Pack many folders and images; existing outputs are skipped.
verify <image_file>	report	Validate an image, optionally against its source.
inspect <image_file>	report	Show metadata and integrity information.
tree <image_file>	file list	List files and folders.
unpack <image_file> <output_dir>	files	Extract an image.
repair <image_file>	repaired image	Fix PFSC blocks the PS5 may decode wrongly.
ampr <subcommand>	JSON	Build and manage AMPR Emu LZ4 asset packs (details).
selftest	—	Check that the bundled native libraries load.

Examples

mkpfs pack exfat PPSA12345-app PPSA12345.exfat              # game folder -> exFAT
mkpfs pack file PPSA12345.exfat PPSA12345.ffpfsc            # exFAT -> compressed image
mkpfs pack folder PPSA12345-app PPSA12345.ffpfsc            # both steps in one pass
mkpfs pack folder PPSA12345-app PPSA12345.ffpfs --raw       # plain PFS (signed, encrypted, PS4...)
mkpfs pack fpkg PPSA12345-app --verify                     # fake-signed debug package, checked
mkpfs batch ./games ./output                                # every game in a folder
mkpfs verify PPSA12345.ffpfsc --source-file PPSA12345.exfat # check against the source
mkpfs inspect PPSA12345.ffpfsc                              # details (--format json for scripts)
mkpfs tree PPSA12345.ffpfsc --deep                          # list files inside the wrapped exFAT
mkpfs unpack PPSA12345.ffpfsc out --deep                    # extract the game files
mkpfs repair PPSA12345.ffpfsc                               # fix risky blocks

Exit codes

Code	Meaning
0	Success.
1	The operation failed.
2	Invalid command line (missing argument, unknown or conflicting options); ampr errors also use 2.
3	repair --scan found blocks that need repair.

Options of pack folder and pack file

The defaults are PS5, 32-bit inodes, case-insensitive names, zlib level 7, 64 KiB blocks and compression on. The output extension is changed to .ffpfsc when needed. Single-file and --raw builds run a quick structure check afterwards; the default exFAT-wrapped pack folder checks only with --verify.

For the default exFAT-wrapped pack folder, compression stays on with 64 KiB blocks. Use --raw to make --no-compress, --block-size, --inode-bits, --max-compressed-ratio, --min-compress-size and --skip-executable-compression take effect.

Compression options

Option	Default	Meaning
--compress / --no-compress	on	Enable or disable PFSC block compression.
--compression-level <0-9>	7	zlib compression level.
--cpu-count <n>	0 (auto)	Compression workers. Auto uses up to 16 and leaves one logical CPU free.
--block-size <bytes|auto|auto-fit>	auto (65536)	Power of two from 4096 to 2097152. auto-fit reduces padding (folder packing and the spool builder).
--threshold-gain <0-100>	0	Keep a compressed block only when it saves at least this percentage.
--max-compressed-ratio <0-100>	100	Store a file raw when PFSC would exceed this percentage of its size.
--min-compress-size <bytes>	block size	Store smaller files raw without trying.
--skip-executable-compression	off	Do not compress important executables.
--compression-backend <...>	auto	Accepted for compatibility; this port always uses zlib 1.3.1.

Image layout and security options

Option	Default	Meaning
--version <PS4|PS5>	PS5	PFS profile version.
--inode-bits <32|64>	32	PFS inode width.
--case-sensitive / --case-insensitive	insensitive	Name comparison mode.
--signed	off	Signed PFS with a zero EKPFS key and seed (not with the exFAT-wrapped pack folder).
--encrypted	off	Encrypt blocks with AES-XTS.
--ekpfs-key <64-hex>	all zeros	EKPFS key; needs --encrypted.

Output, checks and other options

Option	Default	Meaning
--adjust-output-file-extension / --no-adjust-output-file-extension	adjust	Change the extension to match the pack mode, or keep the name as typed.
--temp-folder <dir>	system temp	Where staged files are written.
--verify	off	Full verification after packing instead of the quick structure check.
--verify-structure / --no-verify-structure	on	Turn the quick check on or off.
--skip-verification	off	Skip every post-pack check; not with --verify.
--dry-run	off	Scan and report the layout without writing.
--verbose	off	Print per-file decisions.
--raw	off	pack folder: write a plain .ffpfs instead of the exFAT-wrapped .ffpfsc.
--require-game-files	off	pack folder: refuse to pack without sce_sys/param.json and eboot.bin.
--use-spool	off	pack file: use the older staged builder instead of writing straight into the image.
--rename-inner-image / --no-rename-inner-image	rename	pack file: normalize the file name stored inside, or keep it.

pack folder also takes the APR Emu options.

Options of pack exfat

If output is omitted, the image is <titleId>.exfat next to the source folder; an existing folder as output receives that name.

Option	Default	Meaning
--cluster-size <bytes|auto>	auto (65536)	exFAT cluster size; 64 KiB suits ShadowMountPlus.
--free-space <size>	0	Free space inside the image, for example 2GiB. Without it nothing can write to the mounted image.
--overwrite	off	Replace an existing image.
--verbose / --no-progress	off	More output / no progress bar.

It also takes the APR Emu options.

Options of batch

batch finds packable folders and image files in source_dir and writes one .ffpfsc each into output_dir, skipping existing ones. Its compression, profile, naming and encryption options are the same as pack (auto-fit block sizes are not accepted).

Option	Default	Meaning
--overwrite	off	Replace existing images.
--dry-run	off	Report the conversions without writing.
--verify	off	Fully verify each image.

Folder items also take the APR Emu options.

Reading and extracting

Encrypted images take --ekpfs-key <64-hex> (default: all zeros) and --new-crypt (alternate key derivation). PS5 .pkg files take --passcode <32 characters> (default: all zeros). verify, tree and unpack take --format <auto|pfs|exfat>.

Command	Option	Meaning
inspect	--format <text|json>	Human-readable or JSON report.
tree	--deep	List the files inside a wrapped exFAT.
unpack	--deep	Extract the files inside a wrapped exFAT.
	--only <inner-path>	With --deep, extract only this file or folder (repeatable).
	--overwrite, --no-progress	Replace existing output; hide progress.
verify	--source-dir <dir> / --source-file <file>	Compare with the source folder or file (for a .pkg, the folder it was built from).
	--expect-crc32 <hex>	Require this payload CRC32.
	--expect-manifest-sha256 <64-hex>	Require this manifest SHA-256.
	--require-game-files	Warn when sce_sys/param.json, eboot.bin or pfs-version.dat is missing.

Repair

repair works on an unsigned, unencrypted, single-file .ffpfsc. It scans for risky compressed blocks, stores replacements raw, checks their content and cleans unused bytes in the outer PFS.

Option	Default	Meaning
--scan	off	Report only; exit code 3 when blocks need repair.
--bad-blocks <file>	none	Repair the blocks listed in a PS5 Game Compressor bad_blocks.tsv.
--recompress	off	Re-encode repaired blocks with zlib level 7 instead of storing them raw.
--mode <auto|in-place|copy>	auto	auto copies when there is 1.2× the image size free, else rewrites in place. An interrupted in-place repair can leave the image corrupt.
--report-dir <dir>	none	Write summary.json and bad_blocks.tsv.
--no-slack-cleanup	off	Leave unused outer bytes unchanged.
--cpu-count <n>	0 (all cores)	Workers for scanning and repair.

APR Emu

Some PS5 titles use PlayGo/APR and need Drakmor's APR Emu to run from a mounted image: its libraries in the game's fakelib/ and an ampr_emu.index listing every file. MkPFS does not ship the libraries; download them into one folder and pass it with --ampr-libs.

Library	Download	Required
libSceAmpr.sprx	drakmor/ampr_emu	yes
libScePlayGo.sprx	drakmor/pgo_stub	copied when present

Before packing a folder, pack folder, pack exfat and batch:

1. With --ampr-libs, copy the libraries into <game>/fakelib/ when the game is an APR title (sce_sys/playgo-chunk.dat exists) or --ampr-title is given. Identical files are left alone.
2. When fakelib/libSceAmpr.sprx or fakelib2/libSceAmpr.sprx exists, write ampr_emu.index, hashed and sorted the way the emulator looks paths up, so names with accents resolve on the console.

Both steps change the source folder, so the image includes them.

Option	Default	Meaning
--ampr-libs <dir>	none	Folder with libSceAmpr.sprx (and optionally libScePlayGo.sprx).
--ampr-title	off	With --ampr-libs, add the libraries even without playgo-chunk.dat.
--no-ampr-index	off	Do not write ampr_emu.index.
--ampr-skip-regen-if-exists	off	Keep an existing index while it lists exactly the folder's files and sizes.
--ampr-force-regen	off	Always rebuild the index.

Note

• ShadowMountPlus mounts fakelib2/ instead of fakelib/ when both exist, so --ampr-libs warns and leaves fakelib2/ for you to update.
• A folder that also holds AMPR packs (ampr_assets.index) keeps its ampr_emu.index: the packs address files by their row in it. --ampr-force-regen still rebuilds it, which breaks the packs.
• The desktop app keeps an existing index by default.

AMPR asset packs

Warning

Experimental. Keep the original, unpacked game until the packed one has been played on the PS5.

How it works

ampr compresses a game's data files (levels, textures, audio, video) with LZ4 into a few pack files (ampr_assets-*.pak) and a manifest (ampr_assets.index). On the PS5, Drakmor's AMPR Emu decompresses them on the fly, so the game reads the original bytes. Executables, modules and sce_sys are never packed.

flowchart LR
    G["🎮 Game"] -->|"opens data/level1.pak"| E["AMPR Emu<br/>libSceAmpr.sprx"]
    E -->|"reads blocks"| P["📦 ampr_assets-*.pak"]
    P -->|"LZ4 decode"| E
    E -->|"original bytes"| G

Loading

AMPR Emu only serves files that the game reads in ways it intercepts (AMPR reads and ordinary open/read/stat calls). If a game memory-maps a packed file, or reads it another way, the game usually crashes. That is why each game needs its own rules, and why only a test on the console proves that a packed game works.

Requirements

Need	Details
Console	A jailbroken PS5 with ShadowMountPlus.
Game	An AMPR/APR title (loads libSceAmpr).
Emulator	AMPR Emu 0.4.2.1 or newer, the first release that reads packs; older builds are refused.
Mount	Read-only (mount_read_only=1 in ShadowMountPlus, the default).
Rules	A TOML profile for the game, or traces you record yourself.

Packing a game

flowchart LR
    A["📁 Game folder"] --> B{"Profile<br/>for the game?"}
    B -->|"yes"| D["ampr game<br/>--config game.toml"]
    B -->|"no"| C["Record traces<br/>with debug AMPR Emu"]
    C --> D2["ampr game<br/>--traces traces"]
    D --> E["📦 Packed folder<br/>or .exfat"]
    D2 --> E
    E --> F["🎮 Test on the PS5"]

Loading

1. Check that the unpacked game runs with AMPR Emu in its fakelib/.

2. On the AMPR Packs page, choose Build playable game and fill in the game folder, a new output folder, the folder with AMPR Emu's libSceAmpr.sprx, and the game's profile in TOML Configuration (or a Trace folder). Optionally tick Also build an exFAT image. On the command line:

   mkpfs ampr game --root PPSA12345-app --output PPSA12345-packed --fakelib ampr-emu --config game.toml --exfat .

3. Copy the output folder or the .exfat image to the PS5. Play past the menu and load a save or a level, since some files are only read later.

4. Delete the original only after that.

ampr game copies the libraries, writes ampr_emu.index, packs, copies the files that stay loose, and checks that every packed file decodes to the original. The game folder is only read; if a step fails, the output folder is emptied.

Making rules from traces

The debug build of AMPR Emu (for example the 0.4.2.1 test-debug-pack) records every file the game reads through AMPR. MkPFS turns those recordings into rules.

1. Put the debug libSceAmpr.sprx into the unpacked game's fakelib/ and set mount_read_only=0 for this run, so the emulator can write into the game folder.
2. Play a session, then quit the game from the PS5 menu.
3. Copy ampr_commands.bin and ampr_emu.index into a subfolder of a trace folder (for example traces/session1/) before starting the game again. Leave both in the game folder: the emulator needs the index (keep it unchanged until every session and pack is done), and starts a new journal on each launch. More sessions cover more of the game.
4. Put the normal emulator back and set mount_read_only=1 again.
5. Pick the trace folder in Trace folder (--traces traces); the page shows how many sessions it found.

Only files a session read are packed. To also pack the other files of the same types (extensions), tick Also pack files no session read (--pack-untraced-types), then test the parts of the game they belong to.

To save the rules as a profile you can edit and share:

mkpfs ampr profile generate \
  --trace traces/session1/ampr_commands.bin traces/session1/ampr_emu.index \
  --trace traces/session2/ampr_commands.bin traces/session2/ampr_emu.index \
  --output game.toml --pack-untraced-types

When a packed game crashes

The normal AMPR Emu writes no log. To find the file that fails:

1. Build again with Free space inside the image set to 2GiB (--exfat-free-space 2GiB).
2. Put the debug libSceAmpr.sprx into the packed game's fakelib/.
3. Mount the image read-write (image_rw=<image file name> in ShadowMountPlus's config.ini) and start the game.
4. Read ampr_emu.log in the image: apr.pack.open lines are the packed files the game opened, apr.pack.open.fail lines the ones it could not open. Keep those loose in the profile.

When you report a game, include its title, ID and version, the profile or traces used, what happened, and for a crash the ShadowMountPlus log (/data/shadowmount/debug.log) and the console log.

Profile format

Profiles use ampr_emu's TOML format (see its tools/ampr_pack.example.toml). Rules are checked in order and the last match wins; * also matches /.

[pack]
default_action = "loose"        # files no rule matches stay as they are

[[rule]]
action = "compress"             # LZ4, 64 KiB blocks by default
include = ["data/*"]

[[rule]]
action = "loose"                # always keep executables, modules and system files loose
include = ["eboot.bin", "*.prx", "*.sprx", "sce_sys/*", "sce_module/*", "fakelib/*"]

ampr reference

Subcommand	Required	Purpose
game	--root --output, and --config or --traces	Build a folder that runs from packs as is.
pack	--root --ampr-index --output	Write only the pack set (manifest, volumes, CRC file).
verify	--index	Decode every chunk; --root also compares with the source.
unpack	--index --output	Extract packed files (--file <glob>, --overwrite, --no-preserve-mtime).
list	--index	One line per file (--json for details).
inspect	--index	Manifest summary, volumes and runtime settings.
runtime-config	--index --config	Replace the runtime settings from a [runtime] section without repacking.
remove-sources	--index --root	Show the source files the packs replace; --confirm verifies and deletes them.
profile generate	--output, and a session folder or --trace	Rules from traces; --report, --metrics, --runtime-header.
profile batch	<folder or ZIP> --output-dir	One profile per trace session and a summary.json.

Options of ampr game and ampr pack

Option	Default	Meaning
--config <toml>	none	The game's profile.
--traces <folder>	none	Rules from traces instead of a profile.
--pack-untraced-types	off	With --traces: also pack untraced files of the traced types.
--workers <n>	min(8, cores)	Compression threads (1 to 256).
--self-contained	off	Never leave selected files loose; store incompressible blocks uncompressed.
--fakelib <dir>	none	game: AMPR Emu and other libraries to add to fakelib/.
--exfat <file or folder>	none	game: also build an exFAT image.
--exfat-free-space <size>	0	game: free space inside the image, for a debug run.
--skip-verify	off	game: skip the final checks.
--include, --exclude, --include-from, --exclude-from	none	pack: narrow the rules; --exclude forces files loose.
--require-packed <glob>	none	pack: fail if a matching file would stay loose.
--allow-missing	off	pack: leave selected files missing from --root loose.
--no-progress	off	Hide progress.

Note

• ampr pack and ampr profile are ports of ampr_emu's tools/ampr_pack.py (4.0) and tools/ampr_pack_profile.py (4.1), with the same output byte for byte. game, --traces and --pack-untraced-types are MkPFS additions.
• The release emulator loads at most 2,000,000 files, 16,000,000 chunks and 1,024 volumes; pack warns when a set goes over a limit.
• Deploy ampr_emu.index, the manifest, its .runtime file and every volume from the same build. The .crc file is only used by verify and unpack.
• Use an exFAT image or the plain folder, not .ffpfsc: zlib on top of LZ4 makes loading slower.

PS5 debug packages

pack fpkg builds a fake-signed PS5 debug package (.pkg) from a game or homebrew folder for a console that installs debug packages. It produces the same packages as PS5PkgTool: with --compression stored the bytes match PS5PkgTool's except the random RSA padding of the key entries; with auto (the default) the layout and every compress-or-store decision match, but the Kraken streams differ. Memory use stays small whatever the size of the game; packages over 4 GiB and with thousands of files work. Fake packages start games only on firmware 11.60 and below; see Console compatibility.

The folder needs eboot.bin at its root and should have sce_sys/param.json (the content id comes from it). pack fpkg then:

• fake-signs plain ELF modules (eboot.bin, *.elf, *.prx, *.sprx) in the package, never in the folder;
• adds sce_sys/keystone (from the passcode), sce_sys/pfs-version.dat and sce_sys/about/right.sprx;
• moves param.json, the icons and pictures (with their .dds versions) and changeinfo/ into the package header, packs everything else into the game file system;
• refuses file names with non-ASCII characters (PS5PkgTool turns them into ?).

mkpfs pack fpkg PPSA12345-app                          # UP0000-PPSA12345_00-...-A0100-V0100.pkg here
mkpfs pack fpkg PPSA12345-app game.pkg --compression stored --verify
mkpfs pack fpkg homebrew --content-id UP0000-TEST00000_00-HOMEBREW00000000 --title "My App"
mkpfs verify game.pkg --source-dir PPSA12345-app       # every digest, then compare with the folder
mkpfs unpack game.pkg out                              # extract the game files

Option	Default	Meaning
--content-id <id>	contentId of param.json	36-character content id; required when the folder has no param.json.
--passcode <32 chars>	all zeros	The package key is derived from it.
--compression <auto|fast|stored>	auto	Kraken where it pays; fast uses a quicker parse (about twice as fast, a few percent larger); stored does not compress.
--cpu-count <n>	0 (auto)	Kraken workers. Auto uses every logical processor (the encoder gains from hyper-threading); the package is the same whatever the count.
--verify	off	Check the finished package and compare it with the folder.
--dry-run	off	Check the folder and report what would be packed.
--no-fake-sign	off	Pack plain ELF modules unchanged (a debug-mode console only starts fake-signed ones).
--seed <32 hex>	from content id and passcode	Outer image seed; the same folder and options always give the same package.
--timestamp <unix>	SOURCE_DATE_EPOCH or now	Time stamped on every file.
--title, --app-version, --drm-type	title id, 01.00, free	Used only to generate a missing param.json; a supplied one is packed unchanged.
--temp-folder <dir>	next to the package	Where the inner image is staged while building; it is about as large as the game.
--verbose	off	Log every file's placement and compression and the package layout.
--json	off	Print the result as JSON.

Differences from Python MkPFS

Area	MkPFS.CSharp
Output	The same images as Python MkPFS 1.0.0 with its zlib backend. Set SOURCE_DATE_EPOCH for reproducible timestamps.
Compression	Always zlib 1.3.1 (level 7 by default). --compression-backend is ignored: ISA-L output uses back-references the PS5 decodes wrongly.
New commands	repair and ampr.
APR Emu	pack exfat and batch also build ampr_emu.index; --ampr-libs and --ampr-title are new; --ampr-skip-regen-if-exists checks every path and size.
ampr_emu.index	Matches ampr_emu and the console lookup, so files with non-ASCII names are found; skips the emulator's own trace and log files; fakelib2/ also counts.
Fixed bugs	Listed in tools/oracle/README.md.

Switching from Python MkPFS? See MIGRATION.md.

Build from source

Requirement	Details
.NET SDK	10.0.401 or a newer 10.0.4xx (see global.json).
Windows	Visual Studio 2026 with Desktop development with C++ (native zlib and Native AOT).
Linux, macOS	CMake and a C compiler; Linux Native AOT also needs clang and zlib1g-dev.

dotnet build MkPFS.slnx                                # the first build compiles zlib and lz4 in native/
dotnet test --solution MkPFS.slnx                      # parity tests skip without the oracle corpus
dotnet publish src/MkPFS.Cli -r win-x64 -c Release     # native command line
dotnet publish src/MkPFS.Gui -r win-x64 -c Release     # native desktop app

Use linux-x64 or osx-arm64 on those systems. On Windows, Native AOT linking needs the Visual Studio Installer folder (C:\Program Files (x86)\Microsoft Visual Studio\Installer) on PATH.

Project layout

Path	Content
src/MkPFS.Core	Formats and codecs: PFS, PFSC, exFAT, AMPR, crypto, readers, validators.
src/MkPFS.Build	Image builders, compression planner, batch, AMPR packer.
src/MkPFS.Repair	PFSC repair (Game Compressor port).
src/MkPFS.Cli	The mkpfs command line.
src/MkPFS.Gui	The mkpfs-gui desktop app (Avalonia).
native/	zlib 1.3.1, lz4 1.9.4 and the mkpfs_zlib shim.
tests/	Unit tests, byte-for-byte parity tests and headless GUI tests.
tools/oracle	Python oracle scripts (README).

Oracle corpus

The parity tests compare against images and logs made by the Python tools. See tools/oracle/README.md for setup.

uv run --project ../MkPFS python tools/oracle/build_goldens.py --check        # Python MkPFS
python tools/oracle/build_ampr_goldens.py --check                             # ampr_emu ampr_pack.py
uv run --no-project --python 3.12 --with lz4==4.4.5 python tools/oracle/check_ampr_profile.py

Releases

Push a version tag (git tag v2.0.0 then git push origin v2.0.0). The release workflow reruns CI, uploads the archives, SHA256SUMS.txt and release notes, and marks the release as latest. With a VT_API_KEY repository secret (a VirusTotal API key) it also scans every archive and links the reports.

Credits and license

Project	Used for
MkPFS by PSBrew	The Python original this port follows.
PS5 Game Compressor by Juma Sayeh	The PFSC repair logic.
APR Emu by Drakmor	ampr_emu.index and the asset-pack format and tools that ampr ports.
PlayGo stub by Drakmor	libScePlayGo.sprx.
LibProsperoPKG by SvenGDK (GPL-3.0-or-later)	PS5 package research; parts of the PS5 package builder, the Kraken encoder and the Kraken decoder are ported from it (the decoder derives from ooz by Powzix, GPL-3.0).
PS5PkgTool by pearlxcore (GPL-3.0)	The package format pack fpkg reproduces, checked against its output (its engine is used as a black box, not copied).

Third-party components: zlib 1.3.1 (zlib license), LZ4 1.9.4 and Tomlyn (BSD-2-Clause), Avalonia, CommunityToolkit.Mvvm, System.CommandLine and Spectre.Console (MIT), and Material Design Icons (Apache-2.0).

pack fpkg embeds Sony's sce_sys/about/right.sprx, which every debug package carries (PS5PkgTool ships the same file).

Licensed under GPL-3.0-only, like MkPFS; see LICENSE.md. This project is not affiliated with Sony Interactive Entertainment.