build/HOW_TO_FLASH.md

Flashing Ubuntu Touch on BraX3

Follow these steps carefully to flash Ubuntu Touch images onto your BraX3 device.

---

Prerequisites

• ADB and Fastboot tools must be installed on your computer.
• Device must have LunarOS installed.
• USB Debugging enabled (Settings → Developer Options → USB Debugging).
• Unlock the Bootloader.

  Follow the official guide here: How to Unlock the Bootloader of Your BraX3.

---

Flashing Steps

1. Connect your device and verify it is detected:

   adb devices
   

2. Reboot into fastboot mode:

   adb reboot fastboot
   

3. Set Device Slot to slot a:

   fastboot --set-active=a
   

4. Flash the system image:

   fastboot flash system ubuntu.img
   

5. Reboot bootloader:

   fastboot reboot bootloader
   

6. Flash the boot partitions:

   fastboot flash boot_a boot.img
   fastboot flash boot_b boot.img
   

7. Flash the init_boot partitions:

   fastboot flash init_boot_a init_boot.img
   fastboot flash init_boot_b init_boot.img
   

8. Wipe and format userdata for Ubuntu Touch:

   fastboot -w
   fastboot format:ext4 userdata
   

9. Reboot the device:

   fastboot reboot
   

Just make sure your fastboot/adb version is >= 35.0.2-12147458s. First Ubuntu Touch boot may take 5–8 minutes.

---

Troubleshooting

• Device not detected by adb or fastboot:

  • Check your USB cable and port.
  • Install proper USB drivers if on Windows.
  • Make sure USB Debugging is enabled in Developer Options.

• Bootloop after flashing:

  • Recheck that you flashed all images in the correct order.
  • Confirm that you used the latest platform tools.

• Still stuck? Contact us or ask your question on the BraxTech Community Forum.

---

Completion

After the process is complete, reboot your device. Ubuntu Touch should now be installed on your BraX3. 🎉