Ventoid

Ventoid turns an Android phone into a practical Ventoy-style USB preparation tool. Plug in a USB drive over OTG, choose a layout, and prepare bootable USB media without needing a working PC. The bundled payload is the checksum-verified Ventoy 1.1.18 release.

It is built for offline Android OTG workflows, released on F-Droid, licensed as GPL-3.0-only, and includes no ads, no analytics, and no network dependency for normal use.

For the difference between tagged releases and development changes, see the changelog. Upcoming work and remaining release checks are tracked in the roadmap.

Drive setup and progress	Inspect and update

What Ventoid is for

• Emergency repair kits
• Linux installation USBs
• Recovery USB preparation
• Situations where a phone is the only working device
• Users who want a GPL-compliant, offline, ad-free USB preparation tool

Quick Start

1. Install Ventoid from F-Droid or GitHub Releases.
2. Connect a USB drive using Android OTG.
3. Open Ventoid and grant USB permission.
4. Select the target USB device carefully.
5. Choose MBR or GPT layout.
6. Start USB preparation.
7. After Ventoid prepares the drive, remount it if needed, then copy ISO files to the exFAT data partition with Android Files or another file manager.

Ventoid writes to the selected USB drive. This can erase or overwrite existing data. Back up anything important first.

What Ventoid is not

• Ventoid is not the official Ventoy Android app.
• Ventoid is an independent GPL-licensed Android project that prepares Ventoy-style USB media.
• It does not require root.
• It does not download ISO files for you.
• It does not guarantee that every phone, USB drive, hub, or firmware will behave the same way.

Compatibility Notes

• Requires Android USB host / OTG support.
• Requires a USB mass-storage device visible to Android.
• Some phones, USB-C hubs, card readers, or flash drives may behave differently.
• Large ISO files require the exFAT data partition.
• Bundled media includes the Ventoy Secure Boot chain; first boot on a Secure Boot PC may require a one-time MOK enrollment of the Ventoy certificate.
• Boot success still depends on the target computer firmware, Secure Boot settings, MOK enrollment, and ISO compatibility.

Troubleshooting

No USB device is detected

• Confirm that the Android device supports USB host / OTG mode.
• Reconnect the drive after opening Ventoid and grant the USB permission prompt.
• If the drive disconnects or repeatedly disappears, try a direct OTG adapter, a powered hub, or another USB port or drive.

The exFAT data partition is not visible after preparation

Remount or physically reconnect the drive after Ventoid finishes. Android should then expose the exFAT data partition so ISO files can be copied with Android Files or another file manager.

The drive appears read-only

Ventoid does not enable hardware or operating-system write protection. Check for a physical lock switch, reconnect the drive, and inspect the host operating system's disk attributes before preparing it again.

A PC reports error 4098 or a missing ventoy/ventoy.cpio

This indicates that the expected Ventoy payload is missing from the prepared VTOYEFI partition. Prepare the drive again with the latest Ventoid release without disconnecting it during the write. If the error repeats, include the exact message, phone, OTG adapter or hub, drive model, capacity, and Ventoid log in a bug report.

A very large drive fails to prepare

Drives larger than 2TB are supported: Ventoid resolves their capacity with SCSI READ CAPACITY(16) and uses 16-byte read/write commands for sectors past the 32-bit boundary. Choose the GPT layout for these drives, since MBR partition tables cannot describe LBAs beyond 32 bits. If preparation still fails, report the exact drive size, bridge or enclosure model, and error text rather than retrying destructive writes.

Successful and failed hardware combinations can be submitted with the device compatibility form.

Features

USB preparation

• Prepare bootable USB media without a PC
• Write directly to USB mass-storage devices over Android OTG
• Inspect a connected drive read-only: detect an existing Ventoy layout, read its installed version, and see whether the bundled Ventoy is newer
• Update Ventoy on a prepared drive without erasing it: rewrite only the boot files and VTOYEFI payload while the data partition keeps every ISO
• Repair a matching Ventoy version in place; block updates that would downgrade a newer installed version
• List image names and free space on exFAT data partitions, including warnings for zero-byte images; the expanded list shows up to 100 names
• Choose MBR or GPT Ventoy-compatible disk layouts
• Write the Ventoy core image and EFI partition image
• Format the data partition as exFAT for large ISO files

Safety and transparency

• Ship the Ventoy x86_64 Secure Boot chain (Rocky-signed shim + MOK manager) with pinned provenance
• Verify bundled Secure Boot markers before writing
• Validate reserved space before writing, sample written core/EFI sectors for readback verification, and re-analyse the drive after installation
• Show transfer speed and estimated remaining time while writing VTOYEFI
• Keep five stable progress rows for the partition table, core image, exFAT data, Ventoy EFI, and final checks, with progress shown directly on the install action
• No ads
• No analytics
• No network dependency
• GPL-3.0-only source code

Image listing identifies supported filename extensions; it does not prove that an image boots. Sampled readback can miss damage between samples. QEMU checks reach the Ventoy 1.1.18 menu under both BIOS and UEFI for fresh and updated MBR/GPT layouts; ISO guest boots, Secure Boot enforcement, and physical Android OTG workflows still need separate verification.

Install

The recommended install path is F-Droid:

• https://f-droid.org/packages/com.ventoid.app/

GitHub APKs are also attached to tagged releases:

• https://github.com/GPLaider/Ventoid/releases/latest

GitHub APK signing note

Ventoid 0.1.7 and later GitHub APKs use a new GitHub release signing key. If you installed an older GitHub APK, Android may reject an in-place update. Uninstall the older GitHub APK first, then install the latest release, or switch to the F-Droid build.

F-Droid builds are unaffected because F-Droid builds from source and signs packages with its own repository key.

Privacy

Ventoid is designed to work offline. It does not include ads, analytics, tracking SDKs, or network-dependent behavior.

Relationship to Ventoy

Ventoid focuses on Android OTG workflows for preparing Ventoy-style USB media from a phone. Ventoy itself remains the original bootable USB project. This project is independent and aims to provide a clean, GPL-compliant Android implementation for mobile USB preparation.

Project Info

• Package: com.ventoid.app
• Module: app
• Minimum Android SDK: 21
• Target Android SDK: 35
• License: GPL-3.0-only

Key Source Files

• app/src/main/java/com/ventoid/app/MainActivity.kt
• app/src/main/java/com/ventoid/app/install/VentoyInstallCoordinator.kt
• app/src/main/java/com/ventoid/app/installer/VentoyInstaller.kt
• app/src/main/java/com/ventoid/app/installer/ExFatFormatter.kt
• app/src/main/java/com/ventoid/app/usb/UsbMassStorageHelper.kt

Bundled Assets

• app/src/main/assets/boot/boot.img
• app/src/main/assets/boot/core.img
• app/src/main/assets/ventoy/ventoy.disk.img

Ventoid keeps these assets in the repository so the Android project can be built and reviewed without downloading extra binary payloads during the app build.

Build From Source

Ventoid should be verifiable by anyone. You can open the project in Android Studio or build it directly with Gradle from the repository root.

Android Studio

1. Clone the repository.
2. Open the project in Android Studio.
3. Let Gradle sync and install any missing Android SDK components.
4. Build a debug APK from Build > Build Bundle(s) / APK(s) > Build APK(s), or run the app on a device with USB debugging enabled.

Command Line

On Windows, run these commands from the repository root:

.\gradlew.bat :app:testDebugUnitTest
.\gradlew.bat :app:assembleDebug

For a release build on Windows:

.\gradlew.bat :app:assembleRelease

On Linux or macOS:

./gradlew :app:testDebugUnitTest
./gradlew :app:assembleDebug

For a release build on Linux or macOS:

./gradlew :app:assembleRelease

Release signing is optional. If no VENTOID_RELEASE_* environment variables or Gradle properties are set, Gradle generates an unsigned release APK.

To obtain a signed test build without publishing a release, run the GitHub Release APK workflow manually with publish disabled. Leaving tag empty builds the selected branch and retains the signed APK/AAB as a private Actions artifact for seven days. Tag pushes keep the public release behavior.

Release Preflight

Before pushing a new F-Droid metadata update, run the local preflight from the repository root:

pwsh -File .\scripts\Test-FdroidPreflight.ps1 -UpdateMetadata

The preflight keeps the bundled fdroiddata/metadata/com.ventoid.app.yml copy aligned with the current app version, then runs:

• :app:lintRelease
• :app:testDebugUnitTest
• :app:assembleRelease
• :app:bundleRelease

GitHub Actions runs Android verification on pushes and pull requests, plus an F-Droid preflight job on v* tags and manual dispatches.