Too late here now for me to double-check or even say exactly what I've done, but I put the autologin etc/sv stuff back to how it was in beta8 and beta9, which resulted in the freeze during boot attempt into RAM2 mode on qemu. But now I've modified part of w_init and something I just did got it to boot in that RAM2 LABEL mode, which never worked all evening prior. Maybe just luck, but I am hopeful. If so then the problem is not autoboot at all, but a timing issue. I will know if I've solved the issue tomorrow after I've slept - I hope so, but definitely a tricky one this... looking hopeful though - boots ok every time I try in qemu now. However, I'm not using usb stick, so have to double-check on that now (so, yes, maybe fails then - we'll see).
You will have a long wait till I report back though. Maybe ten or twelve hours from now.
EDIT: Sorry, CANCEL ABOVE... Just froze again - must have just been momentary luck... My goodness - I have no idea. Really does look like it is indeed autologin issue - weird one though - trying to think how to debug this further??? Don't myself no much about autologin - though I've used similar agetty autolog lines prior in WDL_Arch with systemd (was fine but maybe a bit different) - problem is, if it doesn't work, it doesn't work - what to do...??? How about a login manager? But why do I find it working in RAM0 mode on this qemu set up I'm trying, but not RAM2 with uc_ro involved? Doesn't actually make any sense to me - the uc_ro stuff seems fine in all my debug checks thus far and can't see the relationship to autologin anyway... OH, RAM0 didn't work just now either, unless I hit wrong selection - I'd be happy to know it didn't work sometimes either - working from RAM only would introduce less time lag of course so makes sense in that way that RAM0 has a better chance...