Corvalent Q77AX - Appendix C EFI BIOS and POST Codes

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Appendix C EFI BIOS and POST Codes
The status code, or POST code, is used to indicate progress during the boot phase. A subset of
these status codes, also known as checkpoints, indicates common phases of the boot process.
Checkpoints are very useful to determine the cause of a failure or problem during the pre-boot
process.
The AMI EFI BIOS follows the Framework model, so the boot phases are:
• Security (SEC) – initial low-level initialization
• Pre-EFI Initialization (PEI) (equivalent to the Bootblock on the AMIBIOS).
• Driver Execution Environment (DXE) (equivalent to the POST in AMIBIOS).
• Boot Device Selection (BDS) – system setup, pre-OS user interface and
selecting a bootable device.
Checkpoint Ranges
Status Code Range Description
0x01 – 0x0B SEC Execution
0x0C – 0x0F SEC Errors
0x10 - -0x2F PEI Execution up to and including memory detection
0x30 – 0x4F PEI Execution after memory detection
0x50 – 0x5F PEI Errors
0x60 – 0x8F DXE Execution up to BDS
0x90 – 0xCF BDS Execution
0xD0 – 0xDF DXE Errors
0xE0 – 0xE8 S3 Resume (PEI)
0xE9 – 0xEF S3 Resume Errors (PEI)
0xF0 – 0xF8 Recovery (PEI)
0xF9 – 0xFF Recovery Errors (PEI)