GammaOS Next v1.2.0 (Anbernic RG406H) Release Notes

Patreon Exclusive Release
Password obtained from Patreon for GammaOS Insider tier supporters: https://www.patreon.com/posts/145437038
This release becomes publicly available to non-supporters on 7th February 2026. The password will be posted here after that date.

Release Date: 9th December 2025

Overview

GammaOS Next v1.2.0 delivers the latest Android 14 / LineageOS 21 build for the Anbernic RG406H.

This update focuses on:

• **Global shader support for system-level screen filtering.
• A fully implemented and bundled GammaEQ UI for system-level audio tuning
• A new HDMI Docking Mode that turns off the internal display and resizes to the external screen resolution when docked
• The full suite of GammaOS-quality-of-life features introduced on the T820 family (universal button remapping, Daijisho + RetroArch integration, GammaRGB, DC dimming emulation, deep sleep mode, performance modes, etc.), adapted for RG406H

Both Full and Lite editions are available for this release.

Editions: Full vs Lite

GammaOS Next v1.2.0 is provided in two editions so you can align the system with your preferred workflow:

• Full edition

  • Includes Google Play Services, Google Play Store, and related Google components.
  • Suitable if you rely on:
    • Play Store for app distribution and updates
    • Google account sync (e.g. Drive, Contacts, Play Games, etc.)
    • Apps that hard-depend on Google Play Services

• Lite edition

  • Ships without Google services or Play Store.
  • Suitable if you:
    • Prefer a minimal, self-contained handheld environment
    • Install apps via alternative stores or sideloading
    • Want to avoid Google account integration on the device

The core GammaOS experience, performance modes, input features, shaders, GammaEQ, and HDMI docking are present in both editions. The difference is primarily around Google integration and bundled services.

Key Features

Android 14 / LineageOS 21 Base

A modern, clean, debloated system stack providing:

• Improved security and permission model
• Better scheduler behavior and responsiveness
• More robust rendering and graphics pipeline compared to legacy vendor builds
• Reduced bloatware for a snappy, focused handheld experience

Daijisho Launcher + RetroArch Integration

Curated out-of-the-box handheld experience:

• Daijisho configured as the primary launcher
• RetroArch pre-configured for core 8/16/32-bit systems (e.g. GB, GBC, GBA, NES, SNES, Genesis, PSX; BIOS not included)
• Consistent console-style front-end tailored to RG406H

Universal Button Remapping

System-wide input flexibility:

• Map any physical button to arbitrary keys or inputs
• Per-game and global layouts possible via GammaOS tooling
• Designed for emulators, Android games, and niche control schemes

Analog Stick Calibration

Fine-grained analog control:

• Adjust analog stick range and deadzone
• Correct drift, asymmetry, and sensitivity issues
• Calibrations feed into the GammaOS input pipeline to improve feel and precision

DC Dimming Emulation

Display comfort enhancements:

• Emulated DC Dimming for panels that exhibit noticeable PWM flicker
• Reduces eye strain during long sessions
• Implemented in a way that balances flicker reduction with color and brightness stability

GammaRGB LED Sync

RGB integration for supported hardware:

• Mirrors on-screen colors to supported RGB LEDs (where present on the device)
• Brightness is synchronized with display backlight behavior where applicable
• Integrated with GammaOS visual pipeline and effect modes

Deep Sleep Mode (cgroup Freeze)

Aggressive power saving mode:

• Deep Sleep Mode uses Linux cgroup freeze mechanisms to hard-freeze selected background apps
• Significantly reduces background power consumption in standby scenarios
• Best used for gaming-focused setups where you control the app set and are aware some apps may not resume perfectly

Screen Rotation Controls

Display and orientation management:

• Enforce landscape-first behavior even when general rotation is disabled
• Better handling of games and apps that expect a particular orientation
• Integrated with Immersive Mode for a console-like feel

App Drawer in Navigation Bar

Quick access to applications:

• Optional app drawer button in the navigation bar
• Quickly switch between any installed app without returning to the home screen
• Useful when jumping between emulators, tools, and launchers while gaming

Performance Governors & Modes

Power/performance control surfaced as clear modes:

• Max Performance

  • Drives CPU/GPU and related clocks to higher operating points
  • Ideal for heavy emulation and demanding Android games

• Normal Performance

  • Dynamic scaling based on load
  • Balanced trade-off between performance and battery life

• Power Save

  • Lowered frequencies and more conservative scheduling
  • Best for light emulation and extended handheld usage

These modes are exposed via Quick Settings tiles, making it trivial to switch profiles in-game.

Quick Settings Tiles

Fast control over GammaOS features:

• One-tap toggles for:
  • Performance profiles
  • Analog sensitivity
  • ABXY remapping
  • Axis inversion
  • D-pad / analog swap
  • Deep Sleep Mode
  • Rotation / orientation behavior
  • GammaRGB / LED behavior (where applicable)
  • Other GammaOS-specific controls such as Immersive Mode, shaders, BFI, and HDMI docking
• Avoids obscure button combinations; everything is explicit and visible in the UI

L2/R2 Button Fixes

Input reliability:

• Ensures proper L2/R2 reporting and behavior in games and apps that rely on correct analog trigger semantics
• Reduces quirks seen in some stock firmwares around shoulder/trigger handling

Relaxed Scoped Storage

File access without the usual Android friction:

• Loosened file-access restrictions in targeted ways
• Emulation front-ends and tools can read/write game libraries with fewer permission issues
• Reduces the need for awkward SAF dialogs and manual permission workarounds

Magisk Root

Advanced user access:

• Magisk pre-integrated for root management
• Compatible with common modules (subject to Android 14 limitations)
• Root can be managed, hidden, or disabled via standard Magisk mechanisms

GammaOS-Next-Specific Enhancements on RG406H

Beyond the shared feature set, v1.2.0 introduces RG406H-specific improvements and new systems.

Global Shader Pipeline

System-wide post-processing shaders:

• Includes CRT-Simple and LCD3x, with future effects planned
• Integrated with rotation, scaling, and RG406H’s display characteristics
• Long-press the Shader Quick Settings tile to access shader configuration

Immersive Mode (Enabled by Default)

Console-style UI baseline:

• Hides status and navigation bars for a more “console” feel
• Swipe from screen edges to temporarily reveal the bars
• Can be toggled via Quick Settings for users who prefer a more traditional Android UI

GammaEQ (System-Level Audio EQ & UI)

GammaEQ is now fully integrated with a dedicated UI on RG406H:

• Operates at or near the fast mixer level where supported
• GammaEQ app/UI included for:
  • Enabling/disabling the engine
  • Selecting, saving, and managing presets
  • Editing advanced EQ and processing parameters without manual setprop work
• Designed for low-latency, clean output suitable for gaming and emulation
• Still backed by system properties for power users and scripting, but normal use flows through the UI

HDMI Docking Mode

Docked console behavior for RG406H:

• When connected to an HDMI display:
  • The internal screen turns off
  • The system resizes to the external display’s resolution
• Intended for TV/monitor play with controllers or external peripherals
• Integrated with GammaOS display management logic to minimize scaling artifacts and mode-switch glitches
• Typically controlled via an HDMI/External Docking-related Quick Settings tile and internal policies

Core System Improvements on RG406H

v1.2.0 further refines the platform:

• Improved task switcher responsiveness and touch handling
• Reduced rendering latency and frame-pacing jitter in common workloads
• Lower background CPU activity, improving thermals and battery life
• More consistent analog and D-pad input handling across emulators
• General frameworks and vendor stability improvements compared to prior internal builds

Device-Specific Enhancements for RG406H

This release includes targeted improvements over stock RG406H firmware:

• Tuned GPU and display pipeline for smoother frame pacing in both 2D and 3D titles
• Refined CPU/governor configuration for more stable sustained performance
• Improved Wi-Fi stability relative to typical vendor baselines
• Thermal profile adjustments to reduce abrupt throttling while protecting the device
• Integration of GammaOS input stack improvements (remapping, calibration, L2/R2 fixes) into the RG406H hardware profile

Flashing Requirements

• Windows Only (Current Release)
  The RG406H v1.2.0 firmware package is currently intended to be flashed from Windows. Future tooling may add support for Linux/macOS.

• Split Archive
  The build may be split into multiple parts for extraction via 7-Zip (for example: .7z.001, .7z.002, .7z.003).
  All parts must be placed in the same folder before extraction.

• Tools & Drivers
  Flashing uses the same underlying process and tooling described in the GammaOS Next Installation Guide for T820 devices:
  https://github.com/TheGammaSqueeze/GammaOSNext/wiki/GammaOS-Next-Installation#anbernic-rg556--rg-cube--rg406h--rg406v--rg476h--rg-slide

Ensure all required drivers and tools from that guide are installed before you begin.

Installation

1. Download the v1.2.0 firmware package for RG406H from the GammaOS Next Releases page.
2. Extract the archive on Windows using 7-Zip:
   • Place all .7z.00x parts in the same folder.
   • Right-click the first part (e.g. .7z.001) and choose “Extract here” (or similar).
   • Wait for extraction to complete; you should end up with a single firmware folder.
3. Follow the detailed flashing steps in the Installation Guide (the process matches the T820 family flow):
   https://github.com/TheGammaSqueeze/GammaOSNext/wiki/GammaOS-Next-Installation#anbernic-rg556--rg-cube--rg406h--rg406v--rg476h--rg-slide
4. After flashing, allow the first boot to complete. This can take several minutes as Android initializes and optimizes apps.

Flashing will erase all user data. Ensure you have backed up anything important before proceeding.

Known Issues

• Additional shader options and GammaEQ presets will continue to be expanded in future updates.
• Deep Sleep Mode can cause some third-party apps to resume imperfectly; if you see issues, disable it for those apps or globally.
• DC Dimming emulation may slightly alter color accuracy on certain panels and at specific brightness levels.
• If you encounter unusual HDMI docking behavior with specific TVs/monitors, or edge cases with Global BFI or GammaEQ, please report with logs.

Stock firmware RG 406H: https://drive.google.com/file/d/1UVdcEFBBagm4Dmj28w8tyiQuGFyVhXAk/view?usp=sharing

Support

For support, feedback, or bug reports, open an Issue here:
https://github.com/TheGammaSqueeze/GammaOSNext/issues

Thank you for your continued support and for helping refine GammaOS Next on the Anbernic RG406H with this v1.2.0 release.