So I have this laptop I’ve bought second hand.
The laptop is an HP Elitebook 840 G5 and I got it working fine but had bios password setup.
I tried contacting the seller but he doesn’t answer.
Anyway, a computer with bios password won’t cut it for me because I like to do things that I need to change stuff in the bios.
I started researching if there was any way to remove or bypass the bios.
I tried several things, including chatting with HP but the only solution they gave me was a very expensive motherboard replacement.
The conclusion I reached was that the only way to remove a bios password is to reprogram the bios with a CH341A programmer.
It’s something I never did but by having a bios chip clip it looked pretty straight forward. I don’t mind having to use a solder iron but if I cant avoid it, I avoid it.
I then search online for hints on what bios chips look like, open the thing up and start looking for what might look like one.
The description I found about about bios chips was that they either had 8 or 16 legs that they always have a small mark on one of the legs and that sometimes they have another mark, usually painted.
The closest to that description I found was this:
It only has one painted mark but it’s the only thing to me that kinda fit the description with the size of what I think a bios chip might have. It’s also from MXic which is supposedly one of the few bios chips manufacturers.
It’s a “MXic MX25L25673GZ41”.
Okay I order the Ch341A programmer with the clip, it arrives and decide to check the clip size with the chip. It matches… everything else with the bios chip description seemed way to small.
That made me think, okay, even though this doesn’t completely fill the description, I’m pretty sure it’s the bios chip!
I set things up as I’ve seen around the internet, install drivers, etc and decide to try detect the chip.
It doesn’t detect it.
I try recliping, different drivers, 3 or 4 different ones and it just can’t detect it. (All drivers I tried were from one download, maybe I should have downloaded different ones?)
I search manually for the chip and choose the closest model number I found.
I then try reading and nothing… At some point I decide to press the verify button, which I shouldn’t have and maybe it’s where I fucked up because I don’t actually know what verify does… I just assumed it was something non destructive.
At no point I pressed the write button as I was aware that would probably break things without being able to read the chip first.
Anyway, had no results.
I then give up for the day, assemble the laptop and it won’t POST.
As soon as I plug the battery it just turns itself on, the keyboard lights up, caps lock blinks a couple times and then the keyboard lights shutdown and the fan ramps up to max and it stays like that until I reset it. Display off the whole time.
So now I don’t exactly know how to proceed and have several doubts…
1. Now I’m unsure what I tried to read was the bios chip. Maybe because I clipped this chip and tried to read it even though it’s not a bios chip it somehow burned? I don’t know exactly what the Ch341A does to read the chip, my guess is that some current has to pass through the chip.
2. Maybe it’s a bios chip, maybe not, but whatever verify did, ruined it?
3. if that’s the bios chip, did I corrupt it somehow and could I fix it by just flashing it!?
I don’t know if I should try to replace the chip, or do something else?
Any tips on how to proceed?
Edit: When I say size I mean the physical size and the spacing of the pins
You’re supposed to use verify after reading (or after writing). You used it without reading the chip?
Also, you said that the size of the BIOS chip was what? Too small? What was the size? An 8 mbit BIOS should have a BIOS flash size of 1 megabyte (MB). A 32 megabit Bios chip will have a Bios file size of 32/8=4 megabytes.
How large was the size of the chip that you read?
If it was much smaller than the BIOS rom file size, you may have read an improper chip that was NOT bus isolated! For example, the Thunderbolt 3 chip is not bus isolated, which means it must NOT be read with a Pomona or other IC clip! It MUST be desoldered from the board and then read. Bios chips are usually bus isolated, so they are safe to read as long as the system is powered off, unplugged and the battery disconnected. Certain SOIC8 chips may also hold the EC ROM or other Roms, so it’s important to make 100% sure that chip is the BIOS chip and not a chip you should not be reading.
Also, did you have the pins aligned correctly? Pin 1 on the clip --pin 1 on the flasher has to align with pin 1 mark on the chip itself. This is usually a very small indentation on the chip. It has NOTHING to do with any painted circle or dot you may see.
That’s all I can tell you here.
I guess I didn’t explain myself properly… when I said size I meant physical size and the spacing of the pins.
Since I wasn’t 100% sure the chip I found was the bios chip, once I had the clip, seeing the clip physical size matched it and that the pins of the chip aligned with the clip pins that reassured me it was probably the bios chip indeed.
It’s size in mbits I have no idea because I’ve never managed to detect or read the chip.
I tried reading the chip but it wasn’t read because no data was pulled at all and then I used verify.
I aligned the red cable of the clip with the dot on the chip. It has no other marking… This is what made me unsure if this is the actual bios chip.