Calling All Techies: Forgotten Bios Password

It would seem that my oh-so-clever friend succeeded in unintentionally outwitting himself. He owns an HP Pavilion ze9400 laptop which he set up to take a bios password before any other functions could be accessed. He suffers from paranoid tendencies, OCD, etc. Unfortunately, he changed the password today and forgot what he changed it to. Due to the nature of the feature by which he must unlock his device, most orthodox methods are rendered useless.

Here's where you guys come in. Does anyone know how to bypass the bios password function? Any suggestions welcome.

Clear it. Somewhere, either on the BIOS or on the motherboard is a way to zap the CMOS settings, with them will go the password.

ETA: forgot you guys don't do hardware design. Here is an article with pictures.

Remove the CMOS battery if possible. Or, try this:
Clearing a BIOS Password

reply to post by AfterInfinity


Usually doing something like this is the only way to go:

www.youtube.com...

...and the moral of the story is...?
Don't put a password on the BIOS unless you're running a business and don't want people screwing around with things.

I pulled the battery and then flipped the jumper on the CMOS pins before to clear the password on a computer. I have no idea if a laptop has the jumper or not.

Originally posted by rickymouse
I pulled the battery and then flipped the jumper on the CMOS pins before to clear the password on a computer. I have no idea if a laptop has the jumper or not.

Usually the answer to that is... not.
...however, removing the battery from the laptop (the laptop battery, not the CMOS battery), unplugging it from the mains, and then removing the CMOS battery... should work.
Leave it unplugged and without the CMOS battery for a minute or two just to make sure everything resets though. Sometimes even a tiny amount of residual power can keep that thing on its original settings.

reply to post by Awen24


Nothing I haven't already told him - repeatedly. Largely throughout his attempts to resolve the issue on his own.

I had a very similar problem in this thread. Those smarter than me helped me out big time!

Take the battery out of the mobo, some boards have a cmos reset button, might take it apart and get a closer look

Great news! My friend remembered his password. As such, bypassing the bios is no longer necessary at this point in time. Many thanks to everyone who offered their assistance, I very much appreciate it. You are all wonderful.

Originally posted by Awen24
Leave it unplugged and without the CMOS battery for a minute or two just to make sure everything resets though. Sometimes even a tiny amount of residual power can keep that thing on its original settings.

Pressing the on button for at least 5 seconds should be enough to drain residual power in the laptop.

Originally posted by Dragonfly79

Originally posted by Awen24
Leave it unplugged and without the CMOS battery for a minute or two just to make sure everything resets though. Sometimes even a tiny amount of residual power can keep that thing on its original settings.

Pressing the on button for at least 5 seconds should be enough to drain residual power in the laptop.

That won't drain the CMOS caps, though. Different circuit.

Originally posted by Bedlam

Originally posted by Dragonfly79

Originally posted by Awen24
Leave it unplugged and without the CMOS battery for a minute or two just to make sure everything resets though. Sometimes even a tiny amount of residual power can keep that thing on its original settings.

Pressing the on button for at least 5 seconds should be enough to drain residual power in the laptop.

That won't drain the CMOS caps, though. Different circuit.

Guess I was lucky with fast draining capacitators as it has worked for me several times. But thanks for the correction, I googled and learned something new, I always assumed cmos capacitators would charge from the psu in case of a dead battery or absent as the os would appear to function just with defaults and off time/date set.

reply to post by Dragonfly79


There's usually a small cap at the RTC, and some sort of FET switch between the always-on 5V and the battery. Some RTC's will run for damn-ever off the cap, others deplete it pretty fast. Depends on the cap and the RTC.

The typical chip is EEPROM and can be reset by pulling power or jumping the chips circuit. Some chips are EPROM and cannot be reset by disconnecting the bios battery.

reply to post by AfterInfinity


You can try the cmos reset as posted by a few other members, ensure you remove the system battery as well as the cmos battery.

Since it's an HP, you might be screwed. The HP business class line of notebooks, starting with I believe the 4510 series, has an embedded security chip. Your bios password is stored on that, not in the cmos, so resetting that does nothing, using cmos killers does nothing. As I've dealt with this through work, and dealing with HP directly, if you have that security chip, you have basically 2 options.

Replace the board entirely (this is what HP would do)
Manually remove the security chip, purchase one online, and solder it on yourself.

I'm far too lazy to google that model to see if it has it, but if the cmos method doesn't work, you just might be screwed.

I use this site daily:

bios-pw.org...

It's _javascript and works with various makes and models of laptops, it will detect the make and model by the serial number you enter (case sensitive) and provide a few possible backdoor passwords.

I use it specifically for Dell latitude 2100 & 2110 netbooks, but it also works on models of hp/comaq toshiba and a few others I believe.

HP screwed us all by using a proprietary bios. Gone are the days of using a bios killer, they don't work on any HP from about 2004 onwards, none that I've dealt with personally that's for sure.