Several stacks on one card

[flamma at correo.ugr.es]

> Something I noticed is that these partitions have to be in the beginning
> of the SD card.
> I wasn't able to boot from partitions starting at the 7GB mark.

I expect not to have done it bad, since I partitioned :
1 boot partition 1
2 rootfs partition 1
3 boot partition 2
4 rootfs partition 2

Anyway, we're still at time for repartitioning.

> Anyway, I used this u-boot menu on the NAND:
[...]

That's usefule! Thank you, I will use that to get an idea of what I have
to write.