Dear Mats,
In message 1024408647.20191212164918@tele2.se you wrote:
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?
In addition to Harald's advice you might also want to consider not reinventing the wheel yet agaib, but instead look into [1] where all these issues have already been solved (and tested, with many projects and a zillion devices in the field).
[1] https://sbabic.github.io/swupdate/
Best regards,
Wolfgang Denk