Comment 2 for bug 1711747

I ran into this as well when trying to add units to a model to test mixed CPU architectures.

The really strange thing is I could always add an amd64 unit.

For example: start with an empty model and specify a constraint for a different architecture e.g. ppc64el. Any new unit/machine will complain if you try specifying something like arm64.

To change the architecture, first add another throwaway amd64 unit or machine (and then remove it).

From there you can add a unit or machine with a different architecture constraint again, e.g. arm64.

Very strange indeed!