• manual flashing to latest u-boot is mandatory! Download the right boot flash for your board: 512,1G,2G, number of RAM chips and appropirate memory speeds. You can obtain numbers from current boot prompt. Copy this flash-image-MEM-RAM_CHIPS-CPU_DDR_boot_sd_and_usb.bin to your FAT formatted USB key, plug it into USB3.0 port and execute from u-boot prompt:

  bubt flash-image-MEM-RAM_CHIPS-CPU_DDR_boot_sd_and_usb.bin spi usb

  After updating your SPI flash with most recent "sd_and_usb" u-boot, you can boot from USB or SD card the exact same way.

• in case you came from stock boot loader or your boot environment was erased somehow, this is what you need to put into u-boot:

  setenv initrd_addr 0x1100000
  setenv image_name boot/Image
  setenv load_script 'if test -e mmc 0:1 boot/boot.scr; then echo \"... booting from SD\";setenv boot_interface mmc;else echo \"... booting from USB/SATA\";usb start;setenv boot_interface usb;fi;if test -e \$boot_interface 0:1 boot/boot.scr;then ext4load \$boot_interface 0:1 0x00800000 boot/boot.scr; source; fi'
  setenv bootcmd 'run get_images; run set_bootargs; run load_script;booti \$kernel_addr \$ramfs_addr \$fdt_addr'
  saveenv

• If you manage to crash your SPI, proceed with SATA boot recovery.
• booting directly from SATA is currently broken.
• rebooting works with 4.14.y and SD media while it is broken with SATA and USB (always stops)

Preparation

Make sure you have a good & reliable SD card and a proper power supply. Archives can be uncompressed with 7-Zip on Windows, Keka on OS X and 7z on Linux (apt-get install p7zip-full). RAW images can be written with Etcher (all OS).

Boot

Insert SD card into a slot and power the board. (First) boot (with DHCP) takes up to 35 seconds with a class 10 SD Card and cheapest board.

Login

Login as root on HDMI / serial console or via SSH and use password 1234. You will be prompted to change this password at first login. Next you will be asked to create a normal user account that is sudo enabled (beware of default QWERTY keyboard settings at this stage).