Why reset cmos after bios upgrade?

thor

I am about to update my mainboard Award bios for the first time and after having read through their guide I see that I need to reset my cmos after flashing to the new bios. Anyone know why this is neccessary?

kwikbreaks

A guess -

The BIOS is a program or at least a set of subroutines.
The CMOS is a set of data read by the BIOS.

If the BIOS changes then it could well be that the new code wants the control data (CMOS) to be in a different format.

Best just follow what the instructions say and avoid bricking anything. I bricked an IP camera earlier this week due to pure stupidity

spannerzone

Yes be careful updating the motherboard BIOS, if the update fails you'll end up with a dead and usually unsuable motherboard....Updating the BIOS is useful if the update provides improved performance but if it only adds more CPU support and that isn't what you're after I'd be inclined to leave it alone..... I've had few problems in past but when a BIOS update fails you've usually got no way to roll back and you're stuck with a dead device.

Although these days manufacturers of almost anything electronic seem to expect customes to update the firmware in their camera, tv, blu ray player and such like.

Toxteth_OGrady

It's not usual to have to reset CMOS after a BIOS flash but as the other posters have said, if it's in the instructions then do it to minimise risk of error. It's only a 30 second job to move the jBatt jumper.

One thing I would however recommend before you flash is to go into the existing BIOS menu and select restore system defaults.

thor

I am flashing the bios because I cannot get my sata dvd recorder working and I have seen that a later version mentions something about providing support for 'certain optical sata devices'.
I just don't see the need for a cmos reset as it is only data and the bios(both before and after flashing) is still an Award bios so should be able to operate with it.
kwikbreaks explanation is the only logical reason I can understand but if so it is still a bit of a daft thing for Award to do as it makes thing more complicated than it should be.
Of course I will still be following instructions and moving those jumpers so I am expecting Mr T to turn up and throw a Marathon at me

JJ_Egan

Flashing firmware normally resorts the BIOS settings to default .

That is date of firmware build not today's date.
Default on all hardware that may mean you have wrong settings or drives not found . Video cards may not be set to correct format if multiple choices . Boot order is default etc etc .
The BIOS does not know what hardware you have nor how you want the machine to work .Case of one BIOS millions of machines with different settings .


jje

thor

That makes sense as well JJ but it is still a bit silly in most cases.
Take my system for example: the current bio version is working fine with my hardware(apart from the sata issue). When I update the bios all the hardware remains the same but after resetting the cmos(either manually or during the flash process) it will be out of tune with my hardware set up and forcing me to enter all the relevant data again.
It does not take long bit it seems a bit pointless to me.

John_Gray

JJ_Egan wrote: »

Flashing firmware normally resorts the BIOS settings to default.

Not in my experience, mostly on Dell servers, PCs and laptops. There seems no good reason for a BIOS flash to touch the CMOS settings or the BIOS settings, unless it's to fix something in them.