I did some more digging into various forums, and have read that HW4 will (probably) only work on 11.4x or higher FSD software build. My new Y (with HW4) came with 2023.20.100.1 which has FSD 11.3.6 - and does not support the FSD Beta functionality, so that at least appears consistent with the 11.4x theory. The question is, when will the FSD 11.4x build be released? What is super annoying to me (besides the obvious poor communication) is that my M3, that I still have, lost FSB Beta on Delivery Day, so from delivery day to whenever 11.4x is released (days, weeks??) I'll not have any FSD Beta. Tesla has a lot of smart people working on this - why couldn't they figure out how to turn off one and switch to the other car simultaneously - especially when you kept your other car? Strange.