I have to say, I am incredibly happy to see that you worked further on this, and it's on bare metal too!
I have wanted to have PostmarketOS (alpine based, mobile oriented Linux) working on my Glo HD for a while and this gives me some motivation to get on it again. It may even be a good idea to make it possible to use this application on an PmOS device, since other mobile devices and hopefully also e-Readers might benefit from it in the long term.
Do you have any documentation on how you managed to boot Alpine on bare metal? It would be great on relative noobs like me who are thinking about porting something too
Thanks a lot for your work!