In my recent adventures with my real Percom AT88-S1, I noticed when booting with an OS that has @HiassofT's Highspeed SIO patch, it will not boot if the drive is spun down. I believe this is because the PERCOM has a minimum 1 second delay to respond as part of it's motor settle wait after spinup. The drive does support querying percom block (obviously ) but no highspeed capability.
The drive does start spinning immediately when the OS starts to send the first commands on bootup, so i