Boot from different partitions based on some condition

[Mats Jansson]

Hi,

I want to set up for an upgrade of our embedded system, using a
special kernel for the upgrade. The standard will be to load the
system from mtd3 (kernel), mtd4 (devicetree) and mtd5 (rootfs).

When an update is to take place I want to run the upgrade system from
mtd0.

So basically I need to have some sort of telling U-boot that it should
launch the upgrade system instead of the standard system.

Any ideas how I set this up?
How to tell u-boot?
How to get u-boot to boot from another partition based on a condition
like that?

Regards
Mats                          mailto:matsmanhav at tele2.se