Für das X250 gibt's ein Bios-Update. Changelog:

CHANGES IN THIS RELEASE
  Version 1.24

[Important updates]
  Nothing.

[New functions or enhancements]
- Updated the Diagnostics module to version 2.09.09.

[Problem fixes]
- Fixed an issue where system might not boot from OS after updating to BIOS 
  Version 1.23 when "Shut down / Start up" of Dynamic Brightness Control 
  feature in Power Manager is enabled.

Aktualisieren geht mit USB Stick wie sonst auch.