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A POST Error Codes, Messages and FRU to Failure Information
The followingtables define POST error codes and their associated messages. The BIOS will
prompt theuser to press a key in case of serious errors. Thestring “Error” precedes some error
messagesto highlight possible system malfunctions. TheBIOS vendor specific error codes are not
listedhere since not all errorcodes are applicable to every platform. AllPOST errors and warnings
are loggedin thesystem event log unless it is full.
After the videoadapter has been successfully initialized, the BIOS indicates the current testing
phase duringPOST by writing a 2-digit hex code to I/O location 80h. Ifa Port-80h card (Postcard)
is installed, it displaysthis 2-digit code on apair of hex display LEDs.
Table 15. Port-80h Code Definition
Code Meaning
CP AMI check point (port-80) code
Table 16. Boot Block POST Codes
Checkpoint
Code
Description
D0h The NMI is disabled. Power-on delay is starting. Next, the initialization code checksum
will be verified.
D1h Initializing the DMA controller, performing the keyboard controller Basic Acceptance Test
(BAT) test, starting memory refresh, and entering 4 GB flat mode next.
D3h Starting memory sizing next.
D4h Returning to real mode. Executing any OEM patches and setting the stack next.
D5h Passing control to the uncompressed code in shadow RAM. The initialization code is
copied to segment 0 and control will be transferred to segment 0.
D6h Control is in segment 0. Next verifying the system BIOS checksum.
If the system BIOS checksum is bad, go to checkpoint code E0h.
Otherwise, going to checkpoint code D7h.
D7h Passing control to the interface module next.
D8h The main system BIOS runtime code will be decompressed next.
D9h Passing control to the main system BIOS in shadow RAM next.
03h The NMI is disabled. Next, checking for a soft reset or a power-on condition.
05h The BIOS stack has been built. Next, disabling cache memory.
06h Uncompressing the POST code next