The HPT366 code is broken - it tries to set the interface to too high a
speed, which leads to error messages at boot time and/or to data
corruption.

The typical effect at boot time is

 hde: set_drive_speed_status: status=0x51 { DriveReady SeekComplete Error }
 hde: set_drive_speed_status: error=0x04 { DriveStatusError }

Fixed thus.