Technical data

Programmable Configuration Data
MVME4100 Single Board Computer Programmer’s Reference (6806800H19B)
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A.6 How to Fix Corrupted VPD Information
If you encounter corrupted VPD information, use the following method to fix the corrupted
data:
z The firmware is designed to reach the prompt with bad VPD.
z Use the vpdEdit command to fix the VPD.
A.7 What if Your Board Has the Wrong VPD?
If your board has the wrong VPD information, the following occurs:
z No warning message is displayed.
z Incorrect VPD information is seen as correct by the firmware.
z The board may hang during startup (no-start condition).
z The board may be very unstable if it reaches the prompt.
z Device drivers, diagnostic tests and firmware commands may hang or fail in unexpected
ways.
A.8 How to Fix Wrong VPD Problems
If you suspect that your board has problems, as a result of wrong VPD information, select SAFE
mode by setting S1:1 ON and reboot the MVME4100. At this point, the firmware will ignore all
SROM contents. Use SROM or the IBM command to change the VPD to the correct parameters.
A.9 Vital Product Data CRC Calculation
When computing the CRC this field (for example, 4 bytes) is set to zero. The CRC only covers
the range as specified in the size field (4-bytes). Integer values are formatted/stored in big-
endian byte ordering. The VPD CRC generation code is shown in the following example.
/*
* vpdGenerateCRC - generate CRC data for the passed buffer
* description: