User Manual

A-1
Appendix A
AMI UEFI BIOS POST Codes
A status code is a data value used to indicate progress during the boot phase. A subset
of these status codes, known commonly as checkpoints, indicate common phases of the
BIOS boot process.
Checkpoints are typically output to I/O port 80h, but Aptio 4.x core can be configured to
send status codes to a variety of sources. Aptio 4.x core outputs checkpoints throughout
the boot process to indicate the task the system is currently executing. Checkpoints are
very useful in aiding software developers or technicians in debugging problems that
occur during the pre-boot process.
A-1 Checkpoint Ranges
Table A-1. 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)