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

CHANGES IN THIS RELEASE
  Version 1.35

[Important updates]
- Update includes a security fix.

[New functions or enhancements]
  Nothing.

[Problem fixes]
-  Fixed an issue where Windows 10 may fail to startup on certain the system 
   that have less than 8 GB of RAM after installing KB4467691.

Aktualisieren geht mit USB Stick wie sonst auch. Läuft gut.