Both A/B partitions update

General Discussions
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1

Why does mender update only update one partition? Why this choice was made instead of update one partition then the other one when the device is rebooted?
This would be more convenient when the active partition goes corrupted. The device would switch the active partition but not change the running software version (as the two versions are different en both partitions).

A/B paritition schem should’nt store the exact same version in both partition, meaning the mender update would update B partition then reboot then update A partition as soons as a B partition is working correctly.
Is there a way to deploy a update on the first partition as soon as the second is correctly updated an rebooted?

Thank you

2

Hi @perceval,

As far as I can see this is not easily done. The main reason here is that it is a very different problem, which needs a different detection and handling scheme. A “corrupted” partition sounds easy, but what would the reasoning be? An accidential write? Bad memory? External manipulation? All of those require different strategies to even identify the problem. Randomly switching back and forth between partitions upon every unexpected reboot (the naive solution) certainly won’t do the trick.

What you are thinking of is essentially redundancy, not an update mechanism. It can certainly be added in some way, but is clearly beyond the scope of an OTA solution.

Greetz,
Josef