Bios Battery 40mAh (CR1220W) >> ERROR 0251: System CMOS checksum bad | eBay
Lenovo手提電腦維修]Lenovo X1 Carbon 開機顯示0251:System CMOS Checksum bad-Default configuration used. Real Time Clock Error-Check Date and Time settings Press Esc to continue or F1 to enter Setup.
What to do with CMOS checksum error (Win10) - Microsoft Community