wiki:gsc/alternate_boot_device

Version 6 (modified by Tim Harvey, 3 months ago) ( diff )

update page removing old and confusing details

  1. Alternate Boot Device
    1. Auto Switch Boot Device

Alternate Boot Device

Some Gateworks family products have an 'Alternate boot device' that can be used for alternate firmware images, such as a flash recovery image:

  • Newport - eMMC vs microSD

Auto Switch Boot Device

The Gateworks System Controller implements an 'Auto Switch Boot Device' feature that can be useful as a firmware recovery mechanism. GSC register R1.6 (SWITCH_BOOT_ENABLE) enables this mode. When this is set and the board powers on it will initiate a countdown timer cleared by the boot firmware that expires in 30 seconds. Therefore if the boot firmware is missing/corrupt the board will power cycle and boot off the alternate device.

To enable from Linux: 

i2cset -f -y 0 0x20 1 0x40      ;# enable R1.6 (SWITCH_BOOT_ENABLE)

To enable from u-boot 

i2c dev 0 && i2c mw 0x20 1 0x40 1     ;# enable R1.6 (SWITCH_BOOT_ENABLE)
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