Changing CMOS battery, can reset upgraded MB Firmware?

[arcturuspica]

Hello,
My cpu couldnt be seen until MB firmware was upgraded while having the old cpu installed.

If CMOS battery dies and gets replaced, does MB retain the upgraded firmware or resets to the original one?

 

[popatim]

It retains the upgraded firmaware. The original is overwritten (ie - gone) when you upgrade firmware unless you have a dual bios motherboard in which case one bios always has the original copy.