47
LED Status Indicators
Hexadecimal Character Table
Hexadecimal 0 1 2 3 4 5 6 7 8 9 A B C D E F
Debug Code 
LED display
0 1 2 3 4 5 6 7 8 9 A B C D E F
Boot Phases
Security (SEC) – initial low-level initialization
Pre-EFI Initialization (PEI) – memory initialization
Driver Execution Environment (DXE) – main hardware initialization
Boot Device Selection (BDS) – system setup, pre-OS user interface & selecting a 
bootable device (CD/DVD, HDD, USB, Network, Shell, …)
Debug Code LED Table
SEC Progress Codes
01
Power on. Reset type detection (soft/
hard)
02 AP initialization before microcode loading
03
System Agent initialization before 
microcode loading
04
PCH initialization before microcode 
loading
06 Microcode loading
07 AP initialization after microcode loading
08
System Agent initialization after 
microcode loading
09 PCH initialization after microcode loading
0B Cache initialization
SEC Error Codes
0C - 0D Reserved for future AMI SEC error codes
0E Microcode not found
0F Microcode not loaded
PEI Progress Codes
10 PEI Core is started
11 Pre-memory CPU initialization is started
12 - 14
Pre-memory CPU initialization (CPU 
module specific)
15
Pre-memory System Agent initialization 
is started
16 - 18
Pre-Memory System Agent initialization 
(System Agent module specific)
19 Pre-memory PCH initialization is started
1A - 1C
Pre-memory PCH initialization (PCH 
module specific)
2B
Memory initialization. Serial Presence 
Detect (SPD) data reading
2C
Memory initialization. Memory presence 
detection
2D
Memory initialization. Programming 
memory timing information
2E
Memory initialization. Configuring 
memory
2F Memory initialization (other)
31 Memory Installed
32 CPU post-memory initialization is started
33
CPU post-memory initialization. Cache 
initialization
34
CPU post-memory initialization. 
Application Processor(s) (AP) 
initialization
35
CPU post-memory initialization. Boot 
Strap Processor (BSP) selection
36
CPU post-memory initialization. System 
Management Mode (SMM) initialization
37
Post-Memory System Agent initialization 
is started
38 - 3A
Post-Memory System Agent initialization 
(System Agent module specific)
3B Post-Memory PCH initialization is started
3C - 3E
Post-Memory PCH initialization (PCH 
module specific)
4F DXE IPL is started
PEI Error Codes
50
Memory initialization error. Invalid 
memory type or incompatible memory 
speed
51
Memory initialization error. SPD reading 
has failed