INT 15 - later PSIBM PS/2, any model/2s - QUERY BOOT REFERENCE PARTITION AX = D602h Return: CF clear on success AH = 00h AL = status of reference-partition boot request 00h boot not requested 01h boot requested CF set on error AH = status (86h for function not supported) SeeAlso: AX=D601h/BL=00h