Storing u-boot environment in SD card FAT partition?

[OOHehir]

Hello, This is not so much of an issue as more as a question on storing the u-boot env in /etc directory in a SD card & modifying them from userspace.

My setup is using a SAMA5D4-Xplained board, meta-atmel, u-boot-at91_2021.04.bb & at the moment we're using SD cards. We'd like to implemented an A/B update strategy (probably with swupdate). For this strategy to succeed,as your no-doubt aware, the update application needs userspace access to u-boot env, in the form of fw_env.config.

It seems this functionality is included in the u-boot-at91 meta-atmel layer (here).

Do you know if such a setup has been tested with u-boot-at91 & if there's any issues in implementing it? Apologies if this is a bit vague but I still trying to get a handle on the complexity..

Some additional info

• I've included in my Yocto build a recipe for libubootenv
• I'll modify the u-boot config to include:

CONFIG_ENV_IS_IN_FAT=y
CONFIG_ENV_FAT_INTERFACE="mmc"
CONFIG_ENV_FAT_DEVICE_AND_PART="0:1"

• swupdate documentation suggests setting PREFERRED_PROVIDER_u-boot-fw-utils = “libubootenv”