Appendix B. Interpreting Firmware Error Codes
The error code is an 8-character (4-byte) hexadecimal code produced by firmware to
identify the potential failing function or FRU in a system. It consists of 5 source code
characters and 3 reason code characters. Individual characters within the error code
have specific field definitions, as defined in the following tables. Table B-1 and
Table  B-2.
Table B-1. Service Reference Code Field Layout
Source Code Reason Code
Byte 0 Byte 1 Byte 2 Byte 3
S1 S2 S3 S4 S5 R1 R2 R3
Table B-2  (Page  1  of  2).  Service Reference Code Field Descriptions
Field Description
S1
Maintenance Package Source that produced the error code.
0  Reserved
1  Reserved
2  POST, Firmware
3  BIST
4 Service Processor, base system controller, etc.
5  Reserved
8 Product specific service guide, MAPs
9  Reserved
A-F  Reserved
S2 Base class
S3-S4 Sub-class
S5 Unique version of the device/FRU type for a particular product.
R1
Device/FRU unique failure reason codes.
1-7 Use in combination with R2, R3 for diagnostic test failure when
maximum isolation was obtained.
8-9 Use in combination with R2, R3 for diagnostic test failure when
maximum isolation was NOT obtained.
A Log analysis of POST error log
B Log analysis of machine check or checkstop error log
C  Reserved
D Diagnostic detected missing resource
E-F  Reserved
    Appendix B. Interpreting Firmware Error Codes B-1