NxDump

NxDump

Android 10+ tool to extract ExeFS and RomFS from your own XCI / NSP / NCA dumps, with updates merged on top (BKTR patching). Material 3, dynamic colour, dark mode. No emulation — extraction only.

Using it

Setup wizard: pick prod.keys (required; title.keys optional), your game folder, and an output folder.

Library: games are listed with icon, version and detected update. Updates found in the folder attach automatically; use Add file to add any NSP/XCI (e.g. a loose update) manually.

Tap a game → choose ExeFS / RomFS, toggle Merge update, Extract. Runs as a foreground service with a notification.

Output: <Output folder>/<Game> [TITLEID] (+ update)/exefs/… and /romfs/…

Build

Android Studio (Ladybug+): open this folder → Run. JDK 17.

CLI: gradle assembleRelease (Gradle 8.10). The release APK is signed with the debug key so it installs directly.

No PC? Push the folder to GitHub — .github/workflows/build.yml builds the APK as a downloadable artifact.

Layout

core/src/com/nxdump/core – pure-Java format/crypto core (PFS0/HFS0, NCA, AES-XTS/CTR/CTR-Ex, BKTR, RomFS, CNMT/NACP, tickets).

app/src/main/java/com/nxdump – Kotlin + Jetpack Compose UI, SAF access, library cache, foreground extraction service.

core/test/run_tests.sh – builds synthetic encrypted NSP/XCI + update on a desktop JVM and verifies byte-exact output.

Notes / limits

Keys: prod.keys needs header_key, and the master key generation the game uses (key-area/titlekek keys are derived if absent).

Tickets embedded in an NSP are used automatically (common titlekey type). Personalised tickets are not supported.

Not supported: NSZ/XCZ (compressed), NCA0, sparse/compressed NCAs, DLC extraction.

Android 11+ won't let you pick the storage root or Download as the output folder – choose a subfolder.