Last updated: July 2026

## What is GammaOS? GammaOS is a custom Android firmware based on LineageOS 19.1 (Android 12). It is designed specifically to improve performance and usability on Anbernic RG405M and RG505 devices.

It comes in two main variants: – **GammaOS** – Includes Google Services and Play Store – **GammaOS Lite** – No Google apps/services (better performance headroom)

## Main Benefits Over Stock Firmware – Cleaner, debloated system – Better performance governors (CPU, GPU, memory) – Fixed 60 Hz refresh rate (stock runs at 61.2 Hz and can cause frame pacing issues) – Display oversharpening corrected – Improved analog stick calibration – Experimental GPU drivers (ported from Retroid Pocket 3+) – Magisk / root included by default – AdGuard ad-blocking enabled by default – Aurora Store included – Daijisho frontend pre-configured with RetroArch

## Pre-configured Systems in Daijisho + RetroArch Optimised settings are included for: – Game Boy – Game Boy Color – Game Boy Advance – NES – SNES – Sega Genesis / Mega Drive – PlayStation 1 (PSX)

**Note:** You must supply your own BIOS files for systems that require them.

## Important Controls & Hotkeys **Performance Mode Toggle** Hold **R3 + L1 + R1** to switch between: – Max Performance – Normal Performance – Power Save

**Button Layout Toggle** Hold **L3 + L1 + R1** to switch between Xbox and Nintendo-style layouts. Setting is saved across reboots.

**RetroArch Hotkeys (RG505)** – Hotkey button: **Select** – Open RetroArch menu: **L3 + R3** – Hold Select + L1 = Slow motion – Hold Select + L2 = Load state – Hold Select + R2 = Save state – Hold Select + R1 = Fast forward – Hold Select + X = Show FPS – Hold Select + Y = Screenshot

## Root / Magisk Notes – Magisk is already included and working. – Ignore any “additional setup required” warnings — these are false positives. – SafetyNet / Zygisk can be enabled in Magisk settings if needed (useful for some Android games).

## What’s Missing – No built-in button-to-on-screen control mapping tool. Alternatives can be installed from the Play Store or Aurora Store.

## Useful Links – GammaOS GitHub: https://github.com/TheGammaSqueeze/GammaOS – RG505 Unbricker (return to stock): https://drive.google.com/file/d/1WNildo8TZDW6L4tzY9SDEjL3NhPGg_gG/view

## Related Notes – See also: Anbernic RG505 – Quick Setup Notes