Thinkpads Forum

A question for those who are familiar with Middleton Bios Update.

Suppose that a T61 has been updated with Middleton Bios Update. When the time comes to replace the BIOS battery and because of my inability to replace it quickly, the BIOS loses it memory.

I presume that the BIOS goes back to factory default settings, and that I would need to re-apply Middleton Bios Update.

Is this correct?

I would hope not! How would the machine know what BIOS happened to be in the non-volatile memory???

Now after enough time you'll lose various settings - the time and date are obvious and usually the first sign that a CMOS battery has failed. But the firmware code of the BIOS itself is burned into non-volatile memory and stays that way until replaced or until some bizarre hardware failure mangles things.

Art

When losing the CMOS power, a BIOS goes only back to the standard/basic settings of that particular BIOS version,
i.e. Middleton BIOS without CMOS battery goes back to basic Middleton settings, no more, no less.
No need to reapply, just put in a fresh CMOS battery.