IBM B50 - Manual (Page 185)

Appendix A. 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 server. The error code consists of 5
source code characters and 3 reason code characters, as shown in the following
table.
Individual characters within the error code have specific field definitions, as defined in
the following table.
Source Code Reason Code
Byte 0 Byte 1 Byte 2 Byte 3
S1 S2 S3 S4 S5 R1 R2 R3
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 A. Interpreting Firmware Error Codes A-1