Bitfields for feature byte 3:
Bit(s)	Description	)
 7	not used
 6-5	reserved
 4	POST supports ROM-to-RAM enable/disable
 3	SCSI subsystem supported on system board
 2	information panel installed
 1	IML (Initial Machine Load) system (BIOS loaded from disk)
 0	SCSI supported in IML
SeeAlso: #00509,#00511,#00512