Hymo is a high-performance hybrid mount meta-module designed for KernelSU. It refactors core logic with native C++ and introduces HymoFS, which hijacks the kernel file system to use VFS mapping directly instead of mounting, achieving a realistic mounting effect.

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Hymo is not just a mount script; it is a complete native daemon designed to solve performance bottlenecks and compatibility issues of traditional shell scripts in complex mounting scenarios.

• High Performance: Core logic is written entirely in C++, discarding inefficient Shell script calls.
• Direct System Calls: Uses modern Linux Mount APIs like fsopen, fsconfig, fsmount, move_mount directly, bypassing mount command-line limitations for finer mount control.
• Blazing Fast Startup: Optimized execution flow ensures module loading adds almost no overhead to system boot time.

Hymo introduces proprietary HymoFS technology, building a three-tier mount strategy:

• HymoFS (Kernel Mode): Opens a kernel interface after patching the kernel source, directly hijacking the underlying file system to implement file mapping instead of mounting, allowing for hot recovery.
• OverlayFS (General Mode): The preferred solution in standard environments, utilizing kernel OverlayFS features for file-level merging.
• Magic Mount (Compatibility Mode): A traditional Bind Mount fallback for old kernels or special partitions.
• Dynamic Decision: The daemon automatically detects the environment to select the best mode, or users can force a specific mode via WebUI.

• Incremental Update: Automatically compares module module.prop and file timestamps at startup.
• Zero Redundant I/O: Only synchronizes changed module files to the working directory, significantly reducing I/O pressure during startup and extending flash memory life.

• Smart Space Management: Automatically detects kernel Tmpfs support during installation. If supported, it skips creating Ext4 images and uses the in-memory file system directly, saving user storage space.
• Tmpfs Priority: Prioritizes building module images in memory at runtime, offering the fastest speed and "burn after reboot" (high stealth).
• Ext4 Image Fallback: Automatically falls back to modules.img loopback image only when the kernel does not support Tmpfs, ensuring functional availability.

Hymo uses a standard Makefile build system and supports cross-compilation.

Prerequisites:

• Android NDK (r25+)
• Node.js & npm (for building WebUI)
• Make & Zip

HymoFS Patch

If you need to use HymoFS, please add the following to your compilation script when compiling the kernel:

wget https://raw.githubusercontent.com/Anatdx/HymoFS/refs/heads/android15_6.6/patch/hymofs.patch
patch -p1 -F 3 < hymofs.patch
echo "CONFIG_HYMOFS=y" >> ./common/arch/arm64/configs/gki_defconfig # Write to defconfig

Or if you are using susfs, add this AFTER the susfs patch：

wget https://raw.githubusercontent.com/Anatdx/HymoFS/refs/heads/android15_6.6/patch/hymofs_with_susfs.patch
patch -p1 -F 3 < yhymofs_with_susfs.patch
echo "CONFIG_HYMOFS=y" >> ./common/arch/arm64/configs/gki_defconfig # Write to defconfig

Build Commands:

# Compile all architectures and package
make zip

# Compile arm64 only and generate test package
make testzip

Install: The generated zip package can be flashed directly in KernelSU Manager.

Hymo comes with a powerful command-line tool hymod for managing the daemon and HymoFS rules.

hymod [OPTIONS] [COMMAND]

• mount: Mount all modules (Default action).
• modules: List all active modules.
• storage: Show current storage status (Tmpfs/Ext4).
• reload: Reload HymoFS mappings (scans for changes).
• clear: Clear all HymoFS mappings (Emergency Reset).
• list: List all active HymoFS kernel rules.
• version: Show HymoFS protocol and config version.
• gen-config: Generate a default configuration file.
• show-config: Display the current configuration.
• add <mod_id>: Manually add a specific module's rules.
• delete <mod_id>: Manually remove a specific module's rules.
• raw <cmd> ...: Execute raw HymoFS low-level commands (add/hide/inject/delete).

• -c, --config FILE: Specify a custom config file path.
• -m, --moduledir DIR: Specify the module directory (default: /data/adb/modules).
• -v, --verbose: Enable verbose logging for debugging.
• -p, --partition NAME: Add a partition to scan (can be used multiple times).

• Meta-Hybrid Mount: Inspiration and prototype basis for this project.
• KernelSU: Powerful Root solutions.
• Libcxx: Android NDK C++ standard library.
• All contributors to this project: Thank you for your efforts.

Disclaimer: This project involves low-level system modifications. Please ensure data backup before use. The developer is not responsible for any data loss or device damage caused by using this module.