I’m trying to unlock the BIOS on my HP EliteDesk 800 G2 SFF. The computer works fine, but the BIOS setup (F10) is locked with an Administrator password that I don’t know. I can still boot with F9, but I need to get rid of the password.
What I’ve done so far:
- I have a CH341A programmer with SOIC8 clip.
- I successfully read the 16 MB BIOS chip and saved my own dump.
- I opened it in UEFITool and located the NVRAM.
- I tried cleaning the NVRAM (filling with FF) and also keeping the header and cleaning only the body.
- After flashing those modified dumps, the PC turns on but I get the message:
“The Shared SPI Flash was recovered from Embedded Controller Flash”
and then the password is back again. - Flashing back my original dump makes the system work normally again (but still locked).
- I also tried flashing the official BIOS from HP, but the system didn’t boot (likely because the HP file isn’t a full 16 MB image).
What I’ve learned:
- The password is in the NVRAM of the BIOS, but this model also has an EC (Embedded Controller) that seems to rewrite it if it detects changes.
- So just cleaning NVRAM with my CH341A isn’t enough, because the EC puts the password back.
What I need:
- Guidance on how this model can really be unlocked.
- Do I necessarily need to program the EC as well? If so, what’s the practical way to do it?
- Is there a way to edit only the password variables inside NVRAM (so the EC doesn’t overwrite it)?
- Or does this model only work if BIOS + EC are both flashed with clean dumps?
At this point I just want to finally get this machine unlocked and usable. Any advice, tips, or clean dumps known to work for this model would be very appreciated.
Thanks a lot in advance.
Help MeeeBios Block
Edit by Fernando: Thread moved into the “BIOS Modding Requests” Category and title customized