Flashing GammaOS Core with Rockchip RKDevTool (WINDOWS ONLY) - TheGammaSqueeze/GammaOSCore GitHub Wiki

This page describes an alternative way to flash GammaOS Core using the Rockchip RKDevTool, rather than using SDDiskTool. This approach can help users who are:

  • Experiencing boot loops.
  • Finding that SDDiskTool does not recognize their SD card.
  • Having other difficulties during the standard flashing process.
  • Or want to flash GammaOS to their EMMC instead of a SD card (supported devices only)

Overview

The video tutorial demonstrates how to flash a Rockchip-based device (such as a Miyoo Flip) with GammaOS Core.

This method can also apply to other Rockchip devices (RK3566 or similar) if you can get them into loader/maskrom mode. (Some devices may show a IDB load fail error if they don't have an eMMC, this is normal and you can proceed as normal)

Prerequisites

  1. Rockchip Driver

    • A Windows PC with the RockUSB driver installed for Rockchip devices.
    • The driver is included in the RKDevTool bundle; if needed, install it from there.

  2. GammaOS Files

    • Download the latest GammaOS Core .img file from GammaOS Core GitHub Releases.
    • (MIYOO FLIP ONLY) Download any required “Gamma Reboot” files, to use the “Reboot to Loader” app. Download here: GammaReboot.zip

  3. RKDevTool

    • Download the RKDevTool_vX.XX.zip (version 2.96 is shown in the video) from here: RKDevTool_Release_v2.96.zip .
    • Unzip it to a convenient location on your PC.

  4. Device-Specific Requirements

    • Some Rockchip devices have an SD card slot (for external storage) and eMMC (internal storage).
    • If your device does not have onboard storage (eMMC), simply power it on without an SD card inserted to force loader/maskrom mode.
    • If your device has eMMC, you can either use the “Reboot to Loader Mode” app (FLIP ONLY) or run adb reboot loader to enter loader mode.

Step-by-Step Instructions

1. Enter Loader/Maskrom Mode

  • Using the “Reboot to Loader Mode” app (Flip devices):

    1. Copy the “Gamma Reboot” files to an SD card.
    2. Insert the SD card into the device.
    3. Launch the “Reboot to Loader Mode” app. The device’s screen may go blank or freeze at a splash screen—this is normal.

  • For devices without eMMC (no internal storage):

    • Eject all SD cards and power on the device. It should automatically enter loader/maskrom mode, though you may not see any display output.

  • For devices with eMMC (via ADB):

    • While the device is running normally, connect it via USB and run: 
      adb reboot loader
    • The device will reboot into loader mode.

2. Confirm Device Connection and Install Drivers

  1. Connect the device to your PC via USB.
  2. Open Device Manager in Windows; you should see a “Rock USB” device (or similar).
  3. If the device isn’t recognized, install (or update) the RockUSB driver included in the RKDevTool ZIP.
    • Right-click the unknown device → Update Driver → Browse to the RKDevTool’s “Driver” folder.

3. Configure RKDevTool

  1. Launch RKDevTool.exe.
  2. In the Download Image (or “Loader”) tab, fill in these fields (if empty):
    • Storage: (leave blank)
    • Address: 0x00000000
    • Name: Loader
    • Path: Browse to RK356x_SPL_loader_*.bin (the exact filename may vary, e.g. RK356x_SPL_loader_v1.01.bin). If using GameMT E5 Plus or having issues, use MiniLoaderAll.bin instead!
  3. Check Write by Address and click Run. (on certain devices without eMMC, you may see IDB load fail, you can ignore this and continue with the rest of the process) image

4. Switch to Maskrom Mode and chose Storage Type

  • In the top menu, click Advanced Function → Go Maskrom.
  • Watch the log panel for “Prepare IDB Success” or “Maskrom Success.”
  • Now go back to the Download Image tab and click Run again like in Step 3.
  • Return to Advanced Function and click Switch Storage → choose SD (if you intend to flash your SD card rather than internal eMMC), otherwise choose EMMC for internal storage. image

5. Flash the GammaOS Firmware

  1. Navigate to the Upgrade Firmware tab.
  2. Click the Firmware button and select your GammaOS .img file (e.g. GammaOS_Core_Beta3.img).
  3. Wait for the tool to read in the firmware details (Fw Ver, Loader Ver, Chip Info, etc.).
  4. Click Upgrade.
  5. Let the process run. You should see messages such as “Download Firmware Start,” “(100%)…,” and finally “Download Firmware Success.” image

6. Reboot and Verify

  • After flashing is complete, the device reboots automatically.
  • You should see the GammaOS splash screen or a quick “erasing” message, followed by a normal first-time setup sequence.
  • The first boot can take a few minutes; watch for any debug messages or LED activity (if applicable).
  • Eventually, you’ll reach the GammaOS setup wizard screen.

Troubleshooting

  • Tool Closes Unexpectedly
    • Sometimes RKDevTool may crash mid-flash. Simply relaunch RKDevTool and repeat the Step 3 – 5 process.
  • Reboot Loops
    • Double-check that you flashed the correct .img for your device type.
    • Confirm you have installed the “Gamma Loader” first if your device requires it.
  • Driver/Connection Issues
    • Try a different USB cable or port.
    • Ensure the RockUSB driver is properly installed with no exclamation marks in Device Manager.