| POST Code Range | |
| Range | Category / Subsystems |
| 00 - 0F | Debug codes: Can be used by any PEIM / driver for debug |
| 10 - 1F | Host Processors: 1F is an unrecoverable CPU error |
| 20 - 2F | Memory / Chipset: 2F is no memory detected or no useful memory detected |
| 30 - 3F | Recovery: 3F indicated recovery failure |
| 40 - 4F | Reserved for future use |
| 50 - 5F | I / O Busses: PCI, USB, ISA, ATA, ect. 5F is an unrecoverable error. Start with PCI. |
| 60 - 6F | Reserved for future use (for new busses) |
| 70 - 7F | Output Devices: All output consoles. 7F is an unrecoverable error |
| 80 - 8F | Reserved for future use (new output console codes). |
| 90 - 9F | Input devices: Keyboard / Mouse. 9F is an unrecoverable error |
| A0 - AF | Reserved for future use (new input console codes). |
| B0 - BF | Boot Devices: Includes fixed media and removable media. BF is an unrecoverable error |
| C0 - CF | Reserved for future use. |
| D0 - DF | Boot device selection |
| E0 - FF | E0 - EE: Miscellaneous codes. Se Table 38. |
| EF : boot/S3 resume failure | |
| F0 - FF: FF processor exception. | |
| POST Codes | |
| Post Code | Description of POST Operations |
| Host Processor | |
| 10 | Power-on initialization of the host processor (Boot Strap Processor) |
| 11 | Host processor cache initialization (including APs) |
| 12 | Starting Application processor initialization |
| 13 | SMM initialization |
| Chipset | |
| 21 | Initializing a chipset component |
| Memory | |
| 22 | Reading SPD from memory DIMMs |
| 23 | Detecting presence of memory DIMMs |
| 24 | Programming timing parameters in the memory controller and the DIMMs |
| 25 | Configuring memory |
| 26 | Optimizing memory settings |
| 27 | Initializing memory, such as ECC init |
| 29 | Memory testing completed |
| PCI Bus | |
| 50 | Enumerating PCI busses |
| 51 | Allocating resources to PCI bus |
| 52 | Hot Plug PCI controller initialization |
| 53 – 57 | Reserved for PCI Bus |
| USB | |
| 58 | Resetting USB bus |
| 59 | Reserved for USB |
| ATA/ATAPI/SATA | |
| 5A | Resetting PATA/SATA bus and all devices |
| 5B | Reserved for ATA |
| SMBus | |
| 5C | Resetting SMBus |
| 5D | Reserved for SMBus |
| Local Console | |
| 70 | Resetting the VGA controller |
| 71 | Disabling the VGA controller |
| 72 | Enabling the VGA controller |
| Remote Console | |
| 78 | Resetting the console controller |
| 79 | Disabling the console controller |
| 7A | Enabling the console controller |
| Keyboard (USB) | |
| 90 | Resetting keyboard |
| 91 | Disabling keyboard |
| 92 | Detecting presence of keyboard |
| 93 | Enabling the keyboard |
| 94 | Clearing keyboard input buffer |
| 95 | Instructing keyboard controller to run Self Test (PS/2 only) |
| Mouse (USB) | |
| 98 | Resetting mouse |
| 99 | Disabling mouse |
| 9A | Detecting presence of mouse |
| 9B | Enabling mouse |
| Fixed Media | |
| B0 | Resetting fixed media |
| B1 | Disabling fixed media |
| B2 | Detecting presence of a fixed media (IDE hard drive detection etc.) |
| B3 | Enabling/configuring a fixed media |
| Removable Media | |
| B8 | Resetting removable media |
| B9 | Disabling removable media |
| BA | Detecting presence of a removable media (IDE, CD-ROM detection, etc.) |
| BC | Enabling/configuring a removable media |
| BDS | |
| Dy | Trying boot selection y (y=0 to 15) |
| PEI Core | |
| E0 | Started dispatching PEIMs (emitted on first report of EFI_SW_PC_INIT_BEGIN EFI_SW_PEI_PC_HANDOFF_TO_NEXT) |
| E2 | Permanent memory found |
| E1, E3 | Reserved for PEI/PEIMs |
| DXE Core | |
| E4 | Entered DXE phase |
| E5 | Started dispatching drivers |
| E6 | Started connecting drivers |
| DXE Drivers | |
| E7 | Waiting for user input |
| E8 | Checking password |
| E9 | Entering BIOS setup |
| EB | Calling Legacy Option ROMs |
| Runtime Phase/EFI OS Boot | |
| F4 | Entering Sleep state |
| F5 | Exiting Sleep state |
| F8 | EFI boot service ExitBootServices ( ) has been called |
| F9 | EFI runtime service SetVirtualAddressMap ( ) has been called |
| FA | EFI runtime service ResetSystem ( ) has been called |
| PEIMs/Recovery | |
| 30 | Crisis Recovery has initiated per user request |
| 31 | Crisis Recovery has initiated by software (corrupt flash) |
| 34 | Loading recovery capsule |
| 35 | Handing off control to the recovery capsule |
| 3F | Unable to recover |
| POST Sequence | |
| Post Code | Description |
| 21 | Initializing a chipset component |
| 22 | Reading SPD from memory DIMMs |
| 23 | Detecting presence of memory DIMMs |
| 25 | Configuring memory |
| 28 | Testing memory |
| 34 | Loading recovery capsule |
| E4 | Entered DXE phase |
| 12 | Starting application processor initialization |
| 13 | SMM initialization |
| 50 | Enumerating PCI busses |
| 51 | Allocating resourced to PCI bus |
| 92 | Detecting the presence of the keyboard |
| 90 | Resetting keyboard |
| 94 | Clearing keyboard input buffer |
| 95 | Keyboard Self Test |
| EB | Calling Video BIOS |
| 58 | Resetting USB bus |
| 5A | Resetting PATA/SATA bus and all devices |
| 92 | Detecting the presence of the keyboard |
| 90 | Resetting keyboard |
| 94 | Clearing keyboard input buffer |
| 5A | Resetting PATA/SATA bus and all devices |
| 28 | Testing memory |
| 90 | Resetting keyboard |
| 94 | Clearing keyboard input buffer |
| E7 | Waiting for user input |
| 01 | INT 19 |
| 00 | Ready to boot |
