[Arm-netbook] u-boot A20 sunxi, added SPL dual MMC boot
Luke Kenneth Casson Leighton
lkcl at lkcl.net
Sun Jun 18 23:56:20 BST 2017
it's a feature that's present in quite a lot of versions of u-boot but
not in the sunxi one: i added a means to check *two* MMC slots in the
early SPL loader.
the problem without such a feature is: you can only boot from one MMC
slot, even if you compile u-boot with support for two MMC slots...
because the early SPL loader *only recognises loading u-boot from one
for those people not familiar with the A20 boot process:
the BROM loads from a very specific sector of either MMC0 or MMC2 (in
that order). maximum code size: 16k bytes. loading a full u-boot is
not possible so u-boot has to be boot-strapped (aka SPL loader). the
*existing* sunxi SPL loader *only* supports loading from a *single*
MMC card slot.
crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68
More information about the arm-netbook