Expanding the number of images supported

[michaelthomasj]

Currently MCUBoot has a limit of 2 on the number of images that it validates.
I think there are use cases where MCUboot needs to validate update more than 2 images. Examples include TrustZone based projects where in addition to the secure and non-secure applications there is a linked module for a WiFi/Bluetooth SoC. Another would be dual core that uses TrustZone.
Has anyone already proposed this or is working on a similar update?

[d3zd3z]

I'm not aware of any discussions about this. I think a good first step would be to analyze the code that deals with multiple images and see how much of it is just hard coded to the two images, and how much uses loop like constructs. The kinds of things that will make it more difficult are when the code refers to the image or slots by names instead of by an index.

[de-nordic]

I do not think we have some specific limit for number of images. I do not think that there is that much hardcoding done, but that needs to be checked. Supporting more would probably cost us some extra ram, but main problem would be the lack of slot-image mapping for anything above two images, at least with what we currently have.