HP does not use one backdoor. It uses three.
Depending on its BIOS, the code on your HP or Compaq belongs to one of three unrelated schemes. Type what the screen shows and all three are tried.
Which HP is which
All three appear after the same thing happens, enough failed password attempts that the firmware stops accepting typing, but they look different on screen, and they are not interchangeable.
| On screen | Example | Scheme |
|---|---|---|
| 10 characters, letters and digits mixed | CNU1234ABC |
Mini and Netbook |
The letter i, then 8 digits |
i 70412809 |
HP's InsydeH2O variant |
| 8 hexadecimal characters, nothing else | A7AF422F |
AMI |
The middle one is a close relative of the plain InsydeH2O scheme on the main free unlocker (same shape of arithmetic, different salt) which is why it needs its own entry rather than reusing that page's. If you are not sure which you have, that is exactly what the single box above is for.
Entering the code
Take whichever candidate the tool returns back to the locked machine and type it at the same prompt, then press Enter. If the machine drops you into setup, it worked, clear or change the password while you are in there, and reboot to confirm it is gone.
Once you are in, set the password to something you will keep. This same prompt will be waiting the next time.
If it did not work
- Re-read the code. A misread 8 for a B, or a dropped character, produces an answer the firmware will never accept. This is by far the most common cause.
- Try every candidate you were given. Where the tool returns more than one, they are ordered by likelihood, not preference.
- Some machines want a reboot between attempts. Power-cycle and fail the password again to get a fresh prompt.
- Business-class HP models are a different problem. ProBook, EliteBook and ZBook machines of recent vintage do not use any of these three, and no generator opens them.
Two things people ask
It gave me two codes. Which is right? Both are candidates. Two of HP's three schemes have a pair of variants differing by a single table entry or a single salt, and the code on screen cannot tell you which one your firmware uses. Try them in the order given.
Is using this legal? On a machine you own, yes: it is your firmware and your password. We ask the same of you here as we do of paying customers, use it on your own laptop. It is not a way into somebody else's.
Wrote a code.txt instead? Start recovery.