B-4
Appendix B: BIOS POST Codes
POST Code
Description
99h
Check for SMART Drive (optional)
9Ah
Shadow option ROMs
9Ch
Set up Power Management
9Dh
Initialize security engine (optional)
9Eh
Enable hardware interrupts
9Fh
Determine number of ATA and SCSI drives
A0h
Set time of day
A2h
Check key lock
A4h
Initialize typematic rate
A8h
Erase F2 prompt
AAh
Scan for F2 key stroke
ACh
Enter SETUP
AEh
Clear Boot flag
B0h
Check for errors
B1h
Inform RomPilot about the end of POST.
B2h
POST done - prepare to boot operating system
B4h
1 One short beep before boot
B5h
Terminate QuietBoot (optional)
B6h
Check password (optional)
B7h
Initialize ACPI BIOS
B9h
Prepare Boot
BAh
Initialize SMBIOS
BBh
Initialize PnP Option ROMs
BCh
Clear parity checkers
BDh
Display MultiBoot menu
BEh
Clear screen (optional)
BFh
Check virus and backup reminders
C0h
Try to boot with INT 19
C1h
Initialize POST Error Manager (PEM)
C2h
Initialize error logging
C3h
Initialize error display function
C4h
Initialize system error handler
C5h
PnPnd dual CMOS (optional)
C6h
Initialize note dock (optional)
C7h
Initialize note dock late
C8h
Force check (optional)
C9h
Extended checksum (optional)
CAh
Redirect Int 15h to enable remote keyboard
CBh
Redirect Int 13h to Memory Technologies
Devices such as ROM, RAM, PCMCIA, and
serial disk
CCh
Redirect Int 10h to enable remote serial video