## Before you start

The board boots from eMMC before the microSD card. On models with eMMC, erase the eMMC before you boot Armbian from a microSD card.

## Installation

1. On a Linux PC, install `pyamlboot` and download the erase loader:

```sh
sudo pip3 install pyamlboot
curl -LO https://dl.radxa.com/zero/images/loader/radxa-zero-erase-emmc.bin
```

2. Hold the USB BOOT button on the board.
3. Connect the USB-C OTG port (marked USB-PWR) to the PC.
4. Release the USB BOOT button.
5. Erase the eMMC. If the eMMC is not fully clear, run the command a second time.

```sh
sudo boot-g12.py radxa-zero-erase-emmc.bin
```

6. Write the image to a microSD card and boot the board from it.

## Notes

- After step 5, the eMMC shows on the PC as a USB storage device. You can write the image directly to it.
- Radxa guide: [Install OS to eMMC](https://docs.radxa.com/en/zero/zero/low-level-dev/install-os-on-emmc).

## Rescue

Use this if the board does not boot after a write to eMMC or SPI.

1. Stop the boot ROM from reading the internal flash. Hold the recovery button,
   or short the eMMC clock pin to ground. Check the vendor documentation for the
   button on your board.
2. Connect the OTG port to the host and power on. The board enters USB boot mode.
3. Write the vendor firmware. Use the Amlogic USB Burning Tool on Windows, or
   [pyamlboot](https://github.com/superna9999/pyamlboot) on Linux.
4. Power off, remove the short, and boot from a microSD card.