Clearing the CMOS using DOS

[Alterk0de]

Hey folks !

I came across this really neat way of clearing the contents of the CMOS without opening your box up and removing the cell.Here's what you do

1.Goto the command prompt ( type in c:\command in run)
2.Type the following

c:\DEBUG
-o 70 ff
-o 71 2e
-q

3.Presto...Now your CMOS is a virgin again


I've tried this out in many boxes.Hope this work in yours !

[Cybr1d]

wouldn't the debug be different from one maker to the other?

[Alterk0de]

I know what you mean.But this works though for most pcs(Don't no why though).I guess the
code depends on the CMOS .Anyone has better answers ???

[Cybr1d]

I know what you mean.But this works though for most pcs(Don't no why though).I guess the
code depends on the CMOS .Anyone has better answers ???

Thats the thing though, we do not know for what makers that debug would work for . If I try that on my Compaq, and it doesn't work...bye bye OS

[Alterk0de]

True .. this method isn't all that specific!.Well...here's another.I didn't write this in the first place because it's kindda bad for the system.


When the computer starts to boot up ( before the password screen comes up), remove the power !.If you are lucky you'll get " CMOS CHECKSUM ERROR" the first time.Keep on trying till it comes! (The cruelties you do to a pc just to get in !!!)

[DeadAddict]

There are different debug scripts out there not sure if they work on all bios. but this site lists two of them and a few other things
http://motherboards.mbarron.net/bios.html

[jeremy85]

I can help a little
the o command for debug is output to a port
I saw this a while ago it won’t work for proprietary bios and it won’t mess up the hd
the hd port is 170 DEFAULT (i believe) be careful playing in debug it will do what u tell it
i have not looked into where u are sending the hex data ff or 2e
but i have a feeling it is a false value that causes corruption
or it is what generic bios (ami) use for reset

[Relyt]

Ok folks,

Why not just restore the defaults. It's not magic or difficult. Just a mouse click away. I don't believe it varies that much from pc to pc. Why mess with fire. Cybr1d hit the nail on the head when he said:

If I try that on my Compaq, and it doesn't work...bye bye OS

cheers

edit: What does this imply?

(The cruelties you do to a pc just to get in !!!)

[nihil]

As Cyber1d and Relyt have suggested messsing with the BIOS is not a good idea.

This is ESPECIALLY true if you have a brand name computer such as Compaq, HP, Dell, IBM etc, as they DO NOT have a "native" BIOS version. It may say "Award" or "AMI", but it isn't!

The "big boys" don't want the cost of running a large help desk operation, so they have custom BIOSes that have a lot of the options removed. This is to stop people who don't know what they are doing from messing around, then ringing up the help desk to get it sorted out. To attempt to use generic or third party tools in this environment is NOT a good idea. Any updates MUST come from the supplier.

The same can be said of old ex-corporate machines that have come from large organisations. The company wants to keep its support costs down and improve security, so it specifies its own custom BIOS. I have even seen a machine where the BIOS would not let you add new hardware, or even replace a broken 3.5" floppy (there was a hidden menu).

I think that the old saying "if it ain't broke don't fix it" is a very good one as far as BIOS is concerned.

Cheers