- Prepare a card with a FAT filesystem. Download a tiny NOOBS LITE zip archive and unpack it into FAT partition. See http://www.raspberrypi.org/help/noobs-setup/ for details.
- Compile barebox.bin image (use rpi_defconfig). Copy it to the SD/microSD card and name it recovery.img.
- Connect to board’s UART (115200 8N1); Use PIN6 (GND), PIN8 (UART_TX), PIN10 (UART_RX) pins.
- Turn board’s power on.