Is BIOS flashback button important?

The button would be useful if you buy a CPU that is not supported until a certain bios revision because you won't make bios until there is a compatible CPU in the socket. The button bypasses that and is the main reason for the button.

comcom said:

What situation do you need to use BIOS reset jumper?

Is using BIOS reset jumper same as removing the CMOS battery and then inserting the CMOS battery?

Does all motherboard has BIOS reset jumper? It seems like all motherboard has the CMOS battery.

ALL motherboards have a CMOS battery.
Most motherboards have a reset jumper.
Yes. It's the same as removing the CMOS battery.

comcom said:

What situation do you need to use BIOS reset jumper?

Is using BIOS reset jumper same as removing the CMOS battery and then inserting the CMOS battery?

Does all motherboard has BIOS reset jumper? It seems like all motherboard has the CMOS battery.

Removing the battery is less fiddly than shorting a jumper. You can also check the battery voltage which can give problems if the open circuit voltage is below 3V.

DONINAUSTIN said:

So you can upgrade the bios without a working CPU? Not sure I understand. In any case, if I but a MB and CPU I make sure the MB has a bios to support the CPU or I use an old CPU.

Yes that is the whole point of the button. You don't want to buy two cpu's when you purchase the motherboard just because you need the first one to get bios and then it becomes useless after flashing just so that the bios is compatible with the cpu you want to use.

They last like 10-15 years maybe 20 if you are lucky

Malneb said:

They last like 10-15 years maybe 20 if you are lucky

Not true. The CMOS battery failed in my previous desktop PC having a Gigabyte motherboard about every 2 years. It would fail to boot if the voltage dropped much below 3V. I do keep my PCs powered off at the mains when not in use.