[U-Boot] Chain loading an u-boot from an u-boot

[Helmut Raiger]

Hi Stefano,
> Hi Helmut,
>
>
> I understand the first two points, but why do you store the kernel again
> with 1bit HW-ECC ? The second U-Boot is able to check with 4bit BCH and
> your NAND requires 4bit.

This is mainly due to performance requirements. Using 4bit BCH
increases overhead and makes DMA (currently not used in the
kernel driver) a lot slower. We thought we might slip through with
1bit HW-ECC, but we will test this (hopefully not in the field this time 
;-) )
> I agree with Andreas' analyses. It seems that the second u-boot
> overwrites your running U-Boot and only if they are identical you have
> no problem, that means that you are not changing the running code.
I double-checked now, the running u-boot is not overwritten.
When the 2nd u-boot relocates it overwrites the first one, but
that shouldn't be a problem. The first u-boot keeps working after
loading (but not running) the second one without issues.

Only the 'go' crashes the system. u-boot starts stand-alone
application fine, just as the kernel. I really can't see the point
why another u-boot should be any different?!

Helmut


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