The Xbox 360 uses Post Codes to report the current step of the boot process . They can be read using 8 post points on the bottom of the motherboard which form a hex byte.
Post Codes List
The "Possible Cause" indicates possible reasons for post code if the unit is displaying an error code on the front panel or hanging on boot.
1BL
Not applicable to Waternoose DD1 , Shiva , or when Secure ROM is not used.
Hex
Name
Description
Possible Cause
0x10
BEGIN
1BL entry point
0x11
FSB_CONFIG_PHY_CONTROL
FSB function 1
FSB fail
0x12
FSB_CONFIG_RX_STATE
FSB function 2
FSB fail
0x13
FSB_CONFIG_TX_STATE
FSB function 3
FSB fail
0x14
FSB_CONFIG_TX_CREDITS
FSB function 4
FSB fail
0x15
FETCH_OFFSET
Fetch 2BL offset from flash
GPU, SB, Nand
0x16
FETCH_HEADER
Fetch 2BL header from flash
0x17
VERIFY_HEADER
Verify 2BL header
Bad 2BL header
0x18
FETCH_CONTENTS
Copy 2BL to SRAM
Bad 2BL image
0x19
HMACSHA_COMPUTE
Compute 2BL HMAC hash
0x1A
RC4_INITIALIZE
Initialize 2BL RC4
0x1B
RC4_DECRYPT
Decrypt 2BL
Bad 2BL image
0x1C
SHA_COMPUTE
Compute 2BL hash
0x1D
SIG_VERIFY
Verify 2BL hash
Bad 2BL signature
0x1E
BRANCH
Branch to 2BL
2BL
Later retail systems uses a split 2BL which added the CB_A and renamed the CB to CB_B. Earlier units and developer systems use a single 2BL.
CB_A
Hex
Name
Description
Possible Cause
0xD0
CB_A entry point
0xD1
READ_FUSES
Read eFUSEs
0xD2
VERIFY_OFFSET_CB_B
Verify CB_B offset from flash
Bad CB_B image
0xD3
FETCH_HEADER_CB_B
Fetch CB_B header from flash
0xD4
VERIFY_HEADER_CB_B
Verify CB_B header
Bad CB_B header
0xD5
FETCH_CONTENTS_CB_B
Copy CB_B to SRAM
Bad CB_B image
0xD6
HMACSHA_COMPUTE_CB_B
Generate CB_B hash
0xD7
RC4_INTIALIZE_CB_B
Initialize CB_B RC4
0xD8
RC4_DECRYPT_CB_B
Decrypt CB_B
Bad CB_B image
0xD9
SHA_COMPUTE_CB_B
Compute CB_B hash
0xDA
SHA_VERIFY_CB_B
Verify CB_B hash
Bad CB_B signature
0xDB
BRANCH_CB_B
Branch to CB_B
CB, SB, and CB_B
Hex
Name
Description
Possible Cause
0x20
2BL entry point, initialize SoC
0x21
INIT_SECOTP
Initialize Secure ROM and eFUSEs
0x22
INIT_SECENG
Initialize security engine
0x23
INIT_SYSRAM
Initialize system RAM
Bad GPU, RAM
0x24
VERIFY_OFFSET_3BL
Verify 3BL offset from flash
Bad 3BL image
0x25
LOCATE_3BL
Locate 3BL in flash
Bad nand image
0x26
FETCH_HEADER_3BL
Fetch 3BL header from flash
0x27
VERIFY_HEADER_3BL
Verify 3BL header
Bad 3BL header
0x28
FETCH_CONTENTS
Copy 3BL to SRAM
Bad 3BL image
0x29
HMACSHA_COMPUTE_3BL
Compute 3BL hash
0x2A
RC4_INITIALIZE_3BL
Initialize 3BL RC4
0x2B
RC4_DECRYPT_3BL
Decrypt 3BL
Bad 3BL image
0x2C
SHA_COMPUTE_3BL
Compute 3BL hash
0x2D
SHA_VERIFY_3BL
Verify 3BL hash
Bad 3BL signature
0x2E
HWINIT
Hardware initialization
Bad GPU, RAM
0x2F
RELOCATE
Relocate to system RAM
0x30
VERIFY_OFFSET_4BL
Verify 4BL offset from flash
Bad nand image
0x31
FETCH_HEADER_4BL
Fetch 4BL header from flash
0x32
VERIFY_HEADER_4BL
Verify 4BL header
Bad 4BL header
0x33
FETCH_CONTENTS_4BL
Copy 4BL to RAM
Bad 4BL image
0x34
HMACSHA_COMPUTE_4BL
Compute 4BL hash
0x35
RC4_INITIALIZE_4BL
Initialize 4BL RC4
0x36
RC4_DECRYPT_4BL
Decrypt 4BL
Bad 4BL image
0x37
SHA_COMPUTE_4BL
Compute 4BL hash
0x38
SIG_VERIFY_4BL
Verify 4BL hash
Bad 4BL signature
0x39
SHA_VERIFY_4BL
Verify 4BL hash
Bad 4BL signature
0x3A
BRANCH
Branch to 4BL
0x3B
PCI_INIT
Initialize PCI
4BL
Hex
Name
Description
Possible Cause
0x40
4BL entry point, setup memory paging
Bad GPU, RAM
0x41
VERIFY_OFFSET
Verify 5BL offset in flash
Bad 5BL image
0x42
FETCH_HEADER
Fetch 5BL header from flash
0x43
VERIFY_HEADER
Verify 5BL header
Bad 5BL header
0x44
FETCH_CONENTS
Copy 5BL to RAM
Bad 5BL image
0x45
HMACSHA_COMPUTE
Compute 5BL hash
0x46
RC4_INITIALIZE
Initialize 5BL RC4
0x47
RC4_DECRYPT
Decrypt 5BL
Bad 5BL image
0x48
SHA_COMPUTE
Compute 5BL hash
0x49
SHA_VERIFY
Verify 5BL hash
Bad 5BL signature
0x4A
LOAD_6BL
Load 6BL
0x4B
LZX_EXPAND
Expand 6BL
0x4C
SWEEP_CACHES
Clear L1 and L2 cache
0x4D
DECODE_FUSES
Decode fuses
0x4E
FETCH_OFFSET_6BL
Fetch 6BL offset from flash
0x4F
VERIFY_OFFSET_6BL
Verify 6BL offset
Bad 6BL offset
0x50
LOAD_UPDATE_1
Load Patch Slot 1
Bad patch slot 1 image
0x51
LOAD_UPDATE_2
Load Patch Slot 2
Bad patch slot 2 image
0x52
BRANCH
Branch to kernel
0x53
DECRYPT_VERIFY_HV_CERT
Decrypt and verify HV cert
Bad HV cert
Panic Codes List
The "Possible Cause" indicates possible reasons for post code if the unit is displaying an error code on the front panel or hanging on boot.
1BL Panics
Hex
Name
Description
Possible Cause
0x81
MACHINECHECK
Panic - Machine Check
0x82
DATA_STORAGE
Panic - Data Storage
0x83
DATA_SEGMENT
Panic - Data Segment
0x84
INSTRUCTION_STORAGE
Panic - Instruction Storage
0x85
INSTRUCTION_SEGMENT
Panic - Instruction Segment
0x86
EXTERNAL
Panic - External
CPU interrupt triggered
0x87
ALIGNMENT
Panic - Alignment
0x88
PROGRAM
Panic - Program
Illegal instruction
0x89
FPU_UNAVAILABLE
Panic - FPU Unavailable
0x8A
DECREMENTER
Panic - Decrementer
0x8B
HYPERVISOR_DECREMENTER
Panic - Hypervisor Decrementer
0x8C
SYSTEM_CALL
Panic - System Call
0x8D
TRACE
Panic - Trace
0x8E
VPU_UNAVAILABLE
Panic - VPU Unavailable
0x8F
MAINTENANCE
Panic - Maintenance
0x90
VMX_ASSIST
Panic - VMX Assist
0x91
THERMAL_MANAGEMENT
Panic - Thermal Management
0x92
WRONG_THREAD
Panic - Wrong Thread
1BL executed on wrong thread
0x93
TOO_MANY_CORES
Panic - Too Many Cores
1BL executer on wrong core
0x94
VERIFY_OFFSET
Panic - Verify 2BL Offset
Bad 2BL offset
0x95
VERIFY_HEADER
Panic - Verify 2BL Header
Bad 2BL header
0x96
SIG_VERIFY
Panic - 2BL Signature Verify
Bad 2BL signature
0x97
NONHOST_RESUME_STATUS
Panic - Non Host Resume Status
0x98
NEXT_STAGE_SIZE
Panic - Next Stage Size
2BL size too large
2BL Panics
Later retail systems uses a split 2BL which added the CB_A and renamed the CB to CB_B. Earlier units and developer systems use a single 2BL.
CB_A
Hex
Name
Description
Possible Cause
0xF0
VERIFY_OFFSET_CB_B
Panic - CB_B Verify Offset
Bad CB_B offset
0xF1
VERIFY_HEADER_CB_B
Panic - CB_B Verify Header
Bad CB_B header
0xF2
SHA_VERIFY_CB_B
Panic - CB_B Signature Verify
Bad CB_B signature
0xF3
ENTRY_SIZE_INVALID_CB_B
Panic - Entry Size Invalid
CB_B size too large
CB, SB, and CB_B
Hex
Name
Description
Possible Cause
0x9B
VERIFY_SECOTP_1
Panic - Verify eFUSE
0x9C
VERIFY_SECOTP_2
Panic - Verify eFUSE
0x9D
VERIFY_SECOTP_3
Panic - Verify Console Type
0x9E
VERIFY_SECOTP_4
Panic - Verify Console Type
0x9F
VERIFY_SECOTP_5
Panic - Verify Console Type
0xA0
VERIFY_SECOTP_6
Panic - Verify 2BL Revocation
2BL LDV mismatch
0xA1
VERIFY_SECOTP_7
Panic - Verify Secure ROM 7
0xA2
VERIFY_SECOTP_8
Panic - Verify Secure ROM 8
0xA3
VERIFY_SECOTP_9
Panic - Verify Secure ROM 9
0xA4
VERIFY_SECOTP_10
Panic - Verify SMC HMAC
Bad SMC HMAC
0xA5
VERIFY_OFFSET_3BL
Panic - Verify 3BL Offset
Bad 3BL offset
0xA6
LOCATE_3BL
Panic - Locate 3BL
Bad nand image
0xA7
VERIFY_HEADER_3BL
Panic - Verify 3BL Header
Bad 3BL header
0xA8
SIG_VERIFY_3BL
Panic - 3BL Signature Verify
Bad 3BL signature
0xA9
HWINIT
Panic - Hardware Init
0xAA
VERIFY_OFFSET_4BL
Panic - Verify 4BL Offset
Bad 4BL offset
0xAB
VERIFY_HEADER_4BL
Panic - Verify 4BL Header
Bad 4BL header
0xAC
SIG_VERIFY_4BL
Panic - 4BL Signature Verify
Bad 4BL signature
0xAD
SHA_VERIFY_4BL
Panic - 4BL Signature Verify
Bad 4BL signature
0xAE
UNEXPECTED_INTERRUPT
Panic - Unknown Interrupt
0xAF
UNSUPPORTED_RAM_SIZE
Panic - Unsupported RAM Size
Bad GPU, RAM
0xB0
VERIFY_CONSOLE_TYPE
Panic - Verify Console Type
Console type mismatch
4BL Panics
Hex
Name
Description
Possible Cause
0xB1
VERIFY_OFFSET
Panic - Verify 5BL Offset
Bad 5BL offset
0xB2
VERIFY_HEADER
Panic - Verify 5BL Header
Bad 5BL header
0xB3
SHA_VERIFY
Panic - 5BL Signature Verify
Bad 5BL signature
0xB4
LZX_EXPAND
Panic - 5BL LZX Decompression
Bad 5BL image
0xB5
VERIFY_OFFSET_6BL
Panic - Verify 6BL Offset
Bad 6BL offset
0xB6
DECODE_FUSES
Panic - Decode Fuses
0xB7
UPDATE_MISSING
Panic - Update Missing
Bad patch slot image
0xB8
SHA_VERIFY_6BL
Panic - 6BL Signature Verify
Bad 6BL signature
Hardware
Debug and Errors
Other Repair Guides