Lenovo ThinkPad S431 Hardware Maintenance Manual page 64

4. To write the box build date, select 4. Write box build date from EEPROM, and follow the instructions
on the screen.
If the system board is being replaced, try to read the ECA information from the old system board and transfer
the information to the new system. If the system board is inoperable, this will not be possible.
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Hardware Maintenance Manual