Works here, here's the text for anyone who can't access it:
> Turns out APFS has an undocumented "VolBootable" flag that we were never setting since, well, it is undocumented, and the boot picker never cared about it (it read it and printed it's state to system log, just did not take any action). Anyway, fix PR-ed to asahi-installer, old installs will have an installer option to set the flag. But still, probably hold off on installing macos betas :P.