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Michal Simek1be82af2023-05-17 09:17:16 +02001Field Fail-Save U-Boot Update
Aleksandar Gerasimovskiefe19292021-12-10 11:07:53 +01002-----------------------------
3Field Fail-Save u-boot update is a feature that allows save u-boot update
4of FOX and XMC products that are rolled out in the field.
5
6The feature is initially implemented for designs based on LS102x SoC, but in
7theory can be used on all designs that are booting from parallel NOR flash.
8
9The implementation expects redundant (secondary) u-boot image on a predefined
10location in the NOR flashu-boot execution will be transferred to the redundant 
11(secondary) u-boot and redundant u-boot will be started if 'updateduboot' envvar
12is set to 'yes'.
13Update logic check_for_uboot_update() has to be invoked from the design early
14before relocation just after SoC initialization, e.g from board_early_init_f or
15misc_init_f functions.
16By design it is expected that primary u-boot image is burned in the factory and
17never updated, and in case u-boot update is required it can flashed and started
18from secondary u-boot location.