Change NOR bootloader settings

Werner Almesberger werner at
Sun Aug 9 23:52:08 CEST 2009

Maximilian Loy wrote:
> So the only thing is to connect the debug board and "saveenv" will be able
> to write to NOR?

It's a bit more complicated. You need to create a new NOR image.
If you choose to continue using u-boot, that NOR image also contains
the environment.

The NOR image is generated with the script in

If you only want to change the environment, edit

If you want to make more sweeping changes, but still use u-boot, you
have to understand what's going on in mknor, particularly the line
that invokes

If you want to switch to Qi, you're - as far as I know - entering
unchartered territory and you may have to tweak Qi to make it boot
from NOR.

The debug board does two things: 1) it controls write access to NOR,
and 2) it provides a way to recover from a failed attempt to change
the NOR. If you make sure you have a good boot loader in NAND, you
can avoid having to deal with 2).

The mknor script explains how to update the NOR. If you have to
recover from scratch (i.e., NAND and NOR both are unbootable), the
program to use is the "devirginator" in the same directory. The
devirginator uses the debug board to bring up the system via JTAG.

My recommendation would be to leave the NOR as it is, and only use
it to update the boot loader. If there are battery problems, an
external charger may provide an easier if not particularly elegant
solution to bring the system to a point where you can fix the NAND.

- Werner

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