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POST Code Ranges
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  

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