GammaOS Installation Guide for Anbernic RG557, RG477M, and RG477V (SP Flash Tool, Full and Lite Builds) - TheGammaSqueeze/GammaOSNext GitHub Wiki

Video Guide

https://www.youtube.com/watch?v=u_NH83XWAAU

Stock firmware

In case at any time you want to return to stock firmware (whether you have an issue with your device, or want to go back to stock for other reasons), you can do so from the following links:

UPDATE 24/12/2025 - Thermal Throttling Patch - To be installed after GammaOS

Please install the updated thermal_safety_protection.zip Magisk module below for additional stability, this WILL reduce max performance slightly to ensure that your device doesn't trigger thermal shutdown. Copy the file to your internal storage on your device, then open the Magisk app (cancel any prompts about updating/additional setup). Open the Modules tab, and choose the Install from storage option. Select the thermal_safety_protection.zip file, and reboot the device.

Choose your flavor:

Maximum stability (use this as your default if you don't expect to push the system to its absolute limits): thermal_safety_protection.zip
Maximum safe performance (still in testing): thermal_safety_protection_2.zip

Prerequisites

⚠️ Windows Only: This guide only works on Windows.

You will need:

7-Zip installed: https://www.7-zip.org/
A Windows PC and a USB-C cable
The GammaOS release files for your device (download all parts from the relevant GitHub release page)
- Example:
  - RG477V_GammaOS_Next_v1.2.1.7z.001
  - RG477V_GammaOS_Next_v1.2.1.7z.002
  - RG477V_GammaOS_Next_v1.2.1.7z.003
  - (and so on, download every part that exists for the release)
The SP Flash Tool package included in the release folder:
- SP_Flash_Tool_V6.2404_Win.zip
The release password (you will be prompted during extraction)
- Password is available on Patreon for early access
- Password becomes public 60 days after the release

Important Storage Disclaimer (Read This First)

⚠️ These devices may have two storage variants: 128GB and 256GB. You MUST follow the steps for your exact storage size. Selecting the wrong flash XML can brick the device.

Before doing anything in SP Flash Tool:

Boot into stock Android (if possible)
Go to Android Settings -> Storage
Confirm whether your device is 128GB or 256GB
Keep this noted, you will select the correct flash_128GB.xml or flash_256GB.xml later

1. Download and Extract the Release

Create a new folder on your PC for the release, then download all release parts into that single folder.
Extract using 7-Zip:
- Right click the .7z.001 file only
- Choose 7-Zip -> Extract to "RGxxx_GammaOS_Next_vX.Y.Z"
- Do not attempt to extract .002/.003 separately, 7-Zip will automatically use them
Enter the password when prompted (Patreon, or public after 60 days).

After extraction, you should see a folder structure similar to this (example):

RG477V_GammaOS_Next_Full_v1.2.1/
RG477V_GammaOS_Next_Lite_v1.2.1/
SP_Flash_Tool_V6.2404_Win.zip

Example (for reference only):

RG477V_GammaOS_Next_v1.2.1/
- RG477V_GammaOS_Next_Full_v1.2.1/
- RG477V_GammaOS_Next_Lite_v1.2.1/
- SP_Flash_Tool_V6.2404_Win.zip

2. Extract SP Flash Tool and Install Drivers

Extract SP_Flash_Tool_V6.2404_Win.zip into a new folder (same method as above).
Open:
- SP_Flash_Tool_V6.2404_Win/Driver/
Install the included MediaTek drivers (VCOM).
- If Windows blocks driver install, you may need to reboot into driver signature enforcement disabled.
Once drivers are installed, launch:
- SP_Flash_Tool_V6.2404_Win/SPFlashToolV6.exe

3. Load the Correct Flash XML (Full or Lite, 128GB or 256GB)

Decide which build you want:
- Full build folder: RGxxx_GammaOS_Next_Full_vX.Y.Z/
- Lite build folder: RGxxx_GammaOS_Next_Lite_vX.Y.Z/
In SP Flash Tool:
- In the top left, under BROM Connection settings, tick:
  - Auto Reboot

Click Choose next to Download-XML, then browse to:
- RGxxx_GammaOS_Next_Full_vX.Y.Z/download_agent/ or
- RGxxx_GammaOS_Next_Lite_vX.Y.Z/download_agent/

Select the correct XML based on your storage size:
- flash_128GB.xml (for 128GB devices)
- flash_256GB.xml (for 256GB devices)

If you are unsure about your storage size, stop here and confirm Android Settings -> Storage first.

4. Format UFS-LUA0 and UFS-LUA1 Only (Manual Format)

Do not format anything except UFS-LUA0 and UFS-LUA1.

In SP Flash Tool, click the Format tab.
Choose Manual Format Flash.
You will perform two formats total (LUA0 then LUA1), using these exact values:

Manual Format Values (for both 128GB and 256GB):

Begin Address: 0x0
Length (hex): 0x400000

Format 1: UFS-LUA0

Select Region: UFS-LUA0
Enter Begin Address: 0x0
Enter Length: 0x400000
Click Start
Connect the device via USB, and ensure it is shut down (powered off).
SP Flash Tool should detect the device and perform the format.
Wait for the success confirmation (green tick).

Format 2: UFS-LUA1

Without disconnecting the device, change Region to: UFS-LUA1
Enter Begin Address: 0x0
Enter Length: 0x400000
Click Start
It should pick up the device immediately and format LUA1.
Wait for the success confirmation (green tick).

That is all that is needed for format.

Do not format UFS-LUA2
Do not format any other region

NOTE: At any point does the SP Flash tool stop responding, follow the FAQ and retry the same step again: https://github.com/TheGammaSqueeze/GammaOSNext/wiki/GammaOS-Installation-Guide-for-Anbernic-RG557,-RG477M,-and-RG477V-(SP-Flash-Tool,-Full-and-Lite-Builds)#faq

5. Flash GammaOS (Download Tab)

Click the Download tab.
Ensure all partitions are ticked.
Confirm the super image is set correctly:
- If "super" is not ticked, tick it.
- If the file path for "super" is blank, double click the blank file path field and select:
  - For Full:
    - RGxxx_GammaOS_Next_Full_vX.Y.Z/super_full.img
  - For Lite:
    - RGxxx_GammaOS_Next_Lite_vX.Y.Z/super_lite.img

Click the Download button.
If prompted or it shows Waiting for device:
- Connect the USB cable to the powered off device
- SP Flash Tool should detect and begin flashing

Flashing time:

This can take up to 10 minutes depending on your USB port and PC.

When complete:

You will see a green confirmation tick icon.

NOTE: At any point does the SP Flash tool stop responding, follow the FAQ and retry the same step again: https://github.com/TheGammaSqueeze/GammaOSNext/wiki/GammaOS-Installation-Guide-for-Anbernic-RG557,-RG477M,-and-RG477V-(SP-Flash-Tool,-Full-and-Lite-Builds)#faq

6. Re-Flash Preloaders (Advanced Mode -> Write Memory)

Now you must write the preloaders again using Write Memory.

Enable Advanced Mode:
- Press Ctrl + Alt + V in SP Flash Tool
Open Write Memory:
- Window (top menu) -> Write Memory

Write preloader_b.bin to UFS-LUA1:
- Tick Auto Reboot (if present in this window)
- Select UFS Area: UFS-LUA1
- Begin Address: 0x0
- Choose file:
  - RGxxx_GammaOS_Next_(Full or Lite)_vX.Y.Z/preloader_b.bin
- Click Write Memory
- Wait for success confirmation (green tick)
Write preloader_a.bin to UFS-LUA0:
- Select UFS Area: UFS-LUA0
- Begin Address: 0x0
- Choose file:
  - RGxxx_GammaOS_Next_(Full or Lite)_vX.Y.Z/preloader_a.bin
- Click Write Memory
- Wait for success confirmation (green tick)

NOTE: At any point does the SP Flash tool stop responding, follow the FAQ and retry the same step again: https://github.com/TheGammaSqueeze/GammaOSNext/wiki/GammaOS-Installation-Guide-for-Anbernic-RG557,-RG477M,-and-RG477V-(SP-Flash-Tool,-Full-and-Lite-Builds)#faq

7. Final Boot

The install is now complete.
The device will reboot and boot into GammaOS.
First boot may take longer than normal.
Android will complete initial setup.

FAQ

Q) Why is this process so complicated? A) Anbernic shipped these devices without unlockable bootloaders. GammaOS installation uses two bypasses:

One to flash the system images using SP Flash Tool
One to enable running code that would normally be blocked by the locked bootloader

Q) My device is not responding when I press Download, Write Memory, or Start format. SP Flash Tool says Waiting for device. A) Use this recovery sequence:

Disconnect USB.
Click the Stop button in SP Flash Tool.
Hold Power + Volume Down for at least 60 seconds.
Keep holding Power + Volume Down and connect the USB cable.
In SP Flash Tool, press the relevant action again (Start, Download, or Write Memory).
If it still does not detect:
- While USB is connected, hold Power + Volume Down again and do not let go until flashing starts
- Detection can take 30 seconds or more, be patient

Q) Do I need to format UFS-LUA2? A) No. For GammaOS install in this guide, you only format:

UFS-LUA0 (0x0 length 0x400000)
UFS-LUA1 (0x0 length 0x400000)

Quick Reference

Step	Action
1	Download all .7z parts into one folder. Extract using 7-Zip by extracting the .001 file only (password required).
2	Extract SP Flash Tool ZIP. Install MediaTek drivers from SP_Flash_Tool_V6.2404_Win/Driver/.
3	Validate storage size in Android Settings -> Storage (128GB or 256GB).
4	SP Flash Tool -> tick Auto Reboot -> Choose Download-XML -> select flash_128GB.xml or flash_256GB.xml from the chosen Full/Lite download_agent folder.
5	Format tab -> Manual Format Flash -> format UFS-LUA0 then UFS-LUA1 only (begin 0x0, length 0x400000).
6	Download tab -> ensure partitions are ticked -> set super_full.img or super_lite.img if needed -> click Download.
7	Advanced Mode (Ctrl+Alt+V) -> Window -> Write Memory -> write preloader_b.bin to UFS-LUA1 @ 0x0, then preloader_a.bin to UFS-LUA0 @ 0x0.
8	Reboot completes -> boot into GammaOS.