Full-portable Android app + data backup and migration. APK + splits, OBB, external data, and private /data/data packed into one streaming .ark archive and faithfully restored on another device with ownership and SELinux contexts repaired.

Kotlin · Jetpack Compose / Material 3 · Rust JNI compression core · Root (libsu) · Shizuku

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⬇ Download APK  ·  Documentation  ·  Report Bug

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Features

• Full app + data migration — backup everything needed to clone an app onto another device
• Streaming .ark archive — GB-scale OBB/game files compress in constant RAM via Rust JNI
• Three codecs — Zstandard (default), ZIP/deflate, 7z/LZMA2
• Ownership & SELinux repair — UID remapping + restorecon so restored apps actually launch
• Honest capability matrix — Shizuku mode tells you upfront that private /data/data is unavailable
• Local backup catalog — Room database tracks all backups with manifest preview
• Material 3 UI — Jetpack Compose with dynamic color on Android 12+

Backends

Backend	Mechanism	Capability
Root	su via libsu (Magisk / KernelSU / APatch)	FULL — APK + OBB + external data + private /data/data
Shizuku	ADB shell (UID 2000) via Shizuku UserService	PARTIAL — APK + OBB + external data (no private data)

Why no private data on Shizuku? The Android kernel sandbox forbids the ADB shell (UID 2000) from reading another app's /data/data/<pkg>. Only a real superuser can. AetherPak never pretends otherwise — Shizuku backups are flagged partial and the UI makes this visible.

Quick Start

Prerequisites

• Android Studio Koala+ or command-line SDK
• JDK 17, Android SDK 34, NDK r26+
• Rust (stable) with Android targets and cargo-ndk

1. Install Rust toolchain

rustup target add aarch64-linux-android armv7-linux-androideabi x86_64-linux-android
cargo install cargo-ndk

2. Build the native compression core

cd rust/aetherpak-core
cargo ndk \
  -t aarch64-linux-android \
  -t armv7-linux-androideabi \
  -t x86_64-linux-android \
  -o ../../core/compress/src/main/jniLibs \
  build --release

3. Build the APK

# From repo root
./gradlew :app:assembleDebug    # Debug APK
./gradlew :app:assembleRelease  # Release APK (requires keystore)

APK output: app/build/outputs/apk/debug/app-debug.apk

Release signing (optional)

Create keystore.properties at the repo root:

storeFile=/absolute/path/to/release.keystore
storePassword=********
keyAlias=aetherpak
keyPassword=********

When absent, release builds fall back to debug signing.

Architecture

                          +-----------------------------------------------+
                          |                    :app                       |
                          |   Jetpack Compose · Material 3 · Navigation  |
                          |   ServiceLocator (manual DI) + ViewModels    |
                          +----------------------+------------------------+
                                                 |
        +---------------+---------+-------+-------+--------+---------------+
        |               |         |       |                |               |
+-------v----+  +------v---+  +--v-----+  +-----v-----+  +-----v-----+  +-----v-----+
| :core:     |  | :core:   |  | :core: |  | :core:     |  | :core:     |  | :core:    |
| access     |  | backup   |  | restore|  | data       |  | compress   |  | common    |
|            |  |          |  |        |  |            |  |            |  |           |
| Root(libsu)|  | AppScan  |  | Restore|  | Room DB    |  | NativeArch |  | Contracts |
| Shizuku    |  | BackupEng|  | UidMap |  | DataStore  |  | JNI loader |  | Models    |
+-----+------+  +----+-----+  +---+----+  +-----------+  +-----+------+  +-----------+
      |               |           |                              |
      |               +-----+-----+------------------------------+
      |                     |                                    |
      |             +-------v------------------------v-----------+
      |             |                                  |
      |             |      rust/aetherpak-core         |
      |             |      libaetherpak.so (cdylib)    |
      |             |      zstd | zip | 7z | tar      |
      |             +----------------------------------+
      |
      |  elevated shell + file I/O
      v
+-----------------------------------------------------+
|  Android device                                      |
|  su (root)  ·  Shizuku UserService (ADB UID 2000)   |
+-----------------------------------------------------+

Module Map

Module	Role
:core:common	Pure contracts: AccessProvider, NativeArchive, BackupEngine, RestoreEngine, manifest, models
:core:access	RootAccessProvider (libsu), ShizukuAccessProvider (AIDL UserService), AccessManager detection
:core:compress	NativeBridge (JNI external decls), AetherArchive : NativeArchive, graceful isAvailable()
:core:backup	AppScanner (enumerate installed apps), BackupEngineImpl (walk -> stream -> manifest)
:core:restore	RestoreEngineImpl (install -> extract -> repair), UidResolver, permission fixing
:core:data	Room AetherDatabase + BackupDao + BackupRepository, SettingsStore (DataStore)
:app	Compose UI (Home, Backup, Restore, Detail, Settings, Access Setup), ServiceLocator DI, theme
rust/aetherpak-core	cdylib native compression core — zstd, zip, 7z, tar streaming

.ark Archive Format

A single streamed container with entries written header-then-payload:

apk/<basename>.apk            Base + split packages
obb/<relative>                /sdcard/Android/obb/<pkg>/...
external_data/<relative>      /sdcard/Android/data/<pkg>/...
private_data/<relative>       /data/data/<pkg>/...         (Root only)
manifest.json                 ALWAYS the final entry         (TOC + provenance)

manifest.json records per-entry: original devicePath, octal mode, source uid/gid, and SELinux seContext. Top-level: sourceUid, isPartial flag.

UID Remapping (Why Restore Works)

Android assigns each app a private Linux UID (AID_APP_START = 10000+) sequentially at install time. The same package gets a different UID on a different device. If restored files keep the old owner, the app crashes on launch.

AetherPak applies a delta remap:

delta       = newAppUid - manifest.sourceUid
remappedUid = originalUid + delta   (only for app-range UIDs 10000..19999)

Then each restored node is chown-ed, chmod-ed, and the tree is restorecon -R-ed. Shared storage (OBB/external on FUSE /sdcard) skips ownership — the kernel manages it.

Usage

1. Access Setup — detects Root/Shizuku, requests grants, states what each backend can/cannot do
2. Home — pick an installed app, see capability banner
3. Backup — choose codec + components, stream progress live, catalogued locally
4. Restore — from local catalogue or open external .ark, manifest preview with warnings

Tech Stack

Layer	Technology
UI	Jetpack Compose, Material 3
DI	Manual ServiceLocator (no Hilt/Koin)
Database	Room (SQLite) + DataStore (Preferences)
Compression	Rust JNI cdylib (zstd 0.13, zip 0.6, sevenz-rust 0.6, tar 0.4)
Root access	libsu 6.0 (topjohnwu)
Shizuku access	Shizuku API 13 + AIDL UserService

License

AetherPak — GNU General Public License v3.0

The Rust native compression core (rust/aetherpak-core) is also available under Apache 2.0.

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Scope & Safety: AetherPak is an owner-scoped tool — it backs up and migrates the device owner's own apps and data. Every privileged action requires explicit Root or Shizuku grant. No credential extraction, no tampering with other users, no network exfiltration.