[Arm-netbook] EOMA68-A20: boot from microsd (SD3)

[Henrik Nordström]

mån 2013-08-12 klockan 16:08 +0100 skrev luke.leighton:

> what's needed to prep a boot image that will by default boot off of
> SD3 instead of SD0?
> we'd like to be sending out CPU Cards that will look for even u-boot on SD3.

Good question if that can be done with livesuit.

But you can get very close. You can build u-boot with MMC support and
chain-loading u-boot from SD3

boot0 (NAND boot) -> boot1 (NAND boot) -> boot.axf (nanda) -> u-boot.bin
(nanda) -> u-boot.bin (raw SD3).

Personally I would settle for u-boot loaded from nand and looking for
uEnv.txt / script.bin in SD3. Those that absolutely want to load their
own u-boot can do that from there. Just make sure to set a unique
variable in the nand u-boot default environment so uEnv.txt / script.bin
can check which version of u-boot are running.

But yes, it is in theory possible to prepare a livesuit image with an
SD3 u-boot SPL. But u-boot SPL and livesuit is not entirely compatible
at the moment so some work is needed.

It should also be possible to hack up a custom boot0 that will look for
SD3 instead of whatever Livesuit recorded in the boot header, but might
be easier to massage u-boot SPL for the purpose.

It is also possible to write u-boot SD3 SPL directly to the NAND boot
area, but procedure for writing to the NAND boot area is still a bit
shaky.

Regards
Henrik