User Tools
Sidebar
This is an old revision of the document!
Table of Contents
VIM4 OS Boot Priority
VIM4 is capable of boot-up from: eMMC, TF Card, SPI-Flash
This page mainly introduces about the first-stage SoC boot. The second-stage OS flashing is possible for USB storage and NVMe, which depends on u-boot configurations
Default option
- TF-Card always have highest priority
- eMMC
- SPI-Flash
U-boot shell usage
We can swap 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
To make the booting priority swap take effect, you can reboot via mcu, or you can reboot the hardware by clicking the Reset button, or plugging the power supply or cable.
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