Table of Contents

VIM4 OS Boot Priority

VIM4 have possibility boot-up from : eMMC, TF Card, SPI-Flash

We talking there only about 1st stage SoC boot, next second stage OS loading possible for any other devices like USB storage's, NVMe etc … and depends from u-boot configurations

Default boot priority

  1. TF-Card always highest priority
  2. eMMC
  3. SPI-Flash

U-Boot shell usage

You can change the boot priority of the eMMC and SPI-Flash via the KBI(Khadas Boot Instructions) from u-boot shell

Change boot priority to: TF-Card ⇒ eMMC ⇒ SPI-Flash 

kvim4# kbi bootmode w emmc

Change boot priority to: TF-Card ⇒ SPI-Flash ⇒ eMMC 

kvim4# kbi bootmode w spi

for apply setting for next boot, need reboot device by RESET button or re-plug power cable or power-off device or reboot via mcu

Linux command-line usage

i2cset -f -y 6 0x18 0x20 1 # setup default eMMC boot-mode
i2cset -f -y 6 0x18 0x20 0 # setup SPI-flash boot-mode

Hot apply setting changes via mcu reboot

i2cset -f -y 6 0x18 0x91 1

OOWOW boot special shortcut

Hold FUNCTION and short press RESET to force boot OOWOW service from SPI-flash, and skip other boot sources

TF-card slot must be empty.