Ah, I got it now thanks for the explanation!

Indeed, in your case acquiring uBlue through its ISO was probably the best option; but I'm glad to hear that it worked out in the end!

Anyways, doing it the hard way is helping me learn the intricacies of an immutable system, so I am having fun.

Well said!

Just in case; consider the following:

• Pin your current working deployment with the aforementioned sudo ostree admin pin 0 command. After which it remains accessible regardless unless you unpin it later on. This should allow you a working deployment if all else fails and thus a safe haven to rely on.