starsalt
I think i have the same problem, thing is im not trying to boot from the hdd - im automounting it(fstab). The powered hdd seems to be unrecognized if it's on before the pi is(so my automount is out the window), so what i do is turn the pi on, then turn the external hdd power on then sudo mount -a.
Idk how if booting through hdd though since you need it before you can actually do anything.
Looking for a workaround for this still.