HP probook 640 g2 - does it self destruct with bios chip removal?

[SallowDay]

Hi!

I have multiple hp probook 640 g2s that are bios locked.

I removed one, flashed a clear bios from here. Plugging it back into the laptop, it wont boot, and charging led flashes orange.

I remove the 2nd one's bios chip, which is still locked. Now they both won't boot and do the flashing orange, regardless of which chip is in which laptop.

Even the 2nd won't boot with the 2nd's bios chip, despite being untinkered with.


Could I be missing something? Is it possible these laptops are set not to boot ever again if the bios chip is removed?

[KvnTM]

Re: HP probook 640 g2 - does it self destruct with bios chip removal?

I have multiple hp probook 640 g2s that are bios locked.

What do you mean by bios locked?

I removed one, flashed a clear bios from here. Plugging it back into the laptop, it wont boot, and charging led flashes orange.

Are you sure you flashed the correct bios and resoldered the chip back correctly?

I remove the 2nd one's bios chip, which is still locked. Now they both won't boot and do the flashing orange, regardless of which chip is in which laptop.

Even the 2nd won't boot with the 2nd's bios chip, despite being untinkered with.

You most likely have bad solder connections on your chip. The laptop doesn't know that you desoldered the chip. How should it know anyway?
You are not trying to start the laptops without bios chips soldered in place, are you?..

Is it possible these laptops are set not to boot ever again if the bios chip is removed?

No. Only Apple would do that..

[SallowDay]

Re: HP probook 640 g2 - does it self destruct with bios chip removal?

Bios chip isn't soldered on this motherboard ; there are doors one closes to lock it in place. I could take a picture of it or you.

Can you forgive a neophyte for being at wit's end? Anti theft panic feature was all I could think of.

[KvnTM]

Re: HP probook 640 g2 - does it self destruct with bios chip removal?

Bios chip isn't soldered on this motherboard ; there are doors one closes to lock it in place. I could take a picture of it or you.

Can you forgive a neophyte for being at wit's end? Anti theft panic feature was all I could think of.

The bios chip is socketed? That is really uncommon and I never heard of it on laptops.
I looked at some pictures of the board and the bios rom is soldered as to what I can see..

Please upload good high res photos of the board (top & bottom) and from the chip you think is the bios.

[rediii]

Re: HP probook 640 g2 - does it self destruct with bios chip removal?

The bios chip is socketed? That is really uncommon and I never heard of it on laptops.
I looked at some pictures of the board and the bios rom is soldered as to what I can see..

Please upload good high res photos of the board (top & bottom) and from the chip you think is the bios.

it was quite common back in the days. today it's really rare, but i've seen some hp business line laptops, that have socketed bios chips! i know, that this probook can have a firmware bug, but it's related to the battery (which was bad and had a recall program). i had a horrible conversation with the hp pro support, they declined to send me a new battery because my device was out of warranty. this was hilarious.

[rediii]

Re: HP probook 640 g2 - does it self destruct with bios chip removal?

Hi!

I have multiple hp probook 640 g2s that are bios locked.

I removed one, flashed a clear bios from here. Plugging it back into the laptop, it wont boot, and charging led flashes orange.

I remove the 2nd one's bios chip, which is still locked. Now they both won't boot and do the flashing orange, regardless of which chip is in which laptop.

Even the 2nd won't boot with the 2nd's bios chip, despite being untinkered with.


Could I be missing something? Is it possible these laptops are set not to boot ever again if the bios chip is removed?

maybe this question is dumb, but did you remove the cmos-battery? the bios password is programed in the tpm chip right? i think you have to edit the original bios file to remove the pw from the security chip or you have to change this chip with a reprogrammed one... don't forget to clean the socket with ipa! i don't have any schematics, but there are many laptops with two bios chips on the mobo!

[KvnTM]

Re: HP probook 640 g2 - does it self destruct with bios chip removal?

it was quite common back in the days. today it's really rare, but i've seen some hp business line laptops, that have socketed bios chips! i know, that this probook can have a firmware bug, but it's related to the battery (which was bad and had a recall program). i had a horrible conversation with the hp pro support, they declined to send me a new battery because my device was out of warranty. this was hilarious.

I've never seen socketed flash chips on modern laptops. The socket and dip package is thicker than modern laptops themself. And I don't think manufacturers will put so8 clamp sockets on their boards. Would make no sense. I know higher end desktop boards have socketed bios chips. I know my Asus board has it too. But on modern laptops? Dont think so.

This issue won't have anything todo with the battery since he messed with some chips and I'm not sure which ones and it was working before.

maybe this question is dumb, but did you remove the cmos-battery? the bios password is programed in the tpm chip right? i think you have to edit the original bios file to remove the pw from the security chip or you have to change this chip with a reprogrammed one...

Removing the cmos battery won't destroy the bios password. Also the password isn't written into the tpm chip. It most likely is inside the EC/KBC/Super IO EEPROM. Wouldn't make sense to put a password into volatile memory. The TPM only contains a hash of your hardware configuration and some keys.


As I said before: Uploading a photo of what the OP did would help a lot. It is unclear what he did. I looked at photos of the board and there is no socketed bios rom or tpm (if the board even has one).

EDIT: I just noticed that boards with i7 and dedicated GPU do have socketed bios chips! Maybe that's what the OP is talking about? Make sure to put it back in the correct orientation. That's really uncommon and rare to find!

[rediii]

Re: HP probook 640 g2 - does it self destruct with bios chip removal?

I've never seen socketed flash chips on modern laptops. The socket and dip package is thicker than modern laptops themself. And I don't think manufacturers will put so8 clamp sockets on their boards. Would make no sense. I know higher end desktop boards have socketed bios chips. I know my Asus board has it too. But on modern laptops? Dont think so.

This issue won't have anything todo with the battery since he messed with some chips and I'm not sure which ones and it was working before.



Removing the cmos battery won't destroy the bios password. Also the password isn't written into the tpm chip. It most likely is inside the EC/KBC/Super IO EEPROM. Wouldn't make sense to put a password into volatile memory. The TPM only contains a hash of your hardware configuration and some keys.


As I said before: Uploading a photo of what the OP did would help a lot. It is unclear what he did. I looked at photos of the board and there is no socketed bios rom or tpm (if the board even has one).

yeah i know that the removal of the cmos bat won't destroy the pw. but it should be removed before you desolder the chip, that's the point. the battery story was just an anecdote. i'm just suggesting what went wrong here

[KvnTM]

Re: HP probook 640 g2 - does it self destruct with bios chip removal?

yeah i know that the removal of the cmos bat won't destroy the pw. but it should be removed before you desolder the chip, that's the point. the battery story was just an anecdote. i'm just suggesting what went wrong here

Removing it won't hurt but is not necessary if you are careful in my opinion. The flash chip isn't powered by it. But yeah.. just for peace of mind

[rediii]

Re: HP probook 640 g2 - does it self destruct with bios chip removal?

Removing it won't hurt but is not necessary if you are careful in my opinion. The flash chip isn't powered by it. But yeah.. just for peace of mind

i completely agree with you.

[mcplslg123]

Re: HP probook 640 g2 - does it self destruct with bios chip removal?

I confirm that a couple of Hp Commercial laptops(probooks) do have socketed bios. I've faced it. I do removed the bios chip from socket and reprogrammed it. Worked without any issues. So the problem faced@Sallowday is bit strange as no heat is needed to remove the chip-so no question of any resistor/cap getting dislocated or any heat related damage. So its bit strange.

[EvilMax]

Re: HP probook 640 g2 - does it self destruct with bios chip removal?

Hmmm, sorry but i have now in front of me exactly this laptop, but he dont have socketed bios...
Here is the pictures...

[SMDFlea]

Re: HP probook 640 g2 - does it self destruct with bios chip removal?

[QUOTE=EvilMax;927394]Hmmm, sorry but i have now in front of me exactly this laptop, but he dont have socketed bios...
Here is the pictures...

Post images here directly ,not external links please.

[KvnTM]

Re: HP probook 640 g2 - does it self destruct with bios chip removal?

Hmmm, sorry but i have now in front of me exactly this laptop, but he dont have socketed bios...
Here is the pictures...

If I look up this board on resellers some have socketed chips and some don't. Really strange. You can even see the silkscreen drawing for the socket.

[EvilMax]

Re: HP probook 640 g2 - does it self destruct with bios chip removal?

Bloody hell, i didnt see the silkscreen...

[KvnTM]

Re: HP probook 640 g2 - does it self destruct with bios chip removal?

Bloody hell, i didnt see the silkscreen...

Still don't know why some boards have a socket and some don't. Maybe they only populate it on higher spec boards? Or they changed it later to save some pennies?

[GValdameri]

Re: HP probook 640 g2 - does it self destruct with bios chip removal?

Hello Friends.
The same problem happened to me this week.
I bought an HP 640 G2 with a startup password.
I removed the BIOS chip and read it as CH431A Programmer version 1.29.
I unlocked the password and saved the BIOS again.
When trying to turn on the notebook, the yellow power light only flashed.
Luckily I had saved the BIOS memory using CH431A Programmer version 1.32.
I unlocked the password again and saved the BIOS.
The notebook turned on and restarted a few times.
Moral of the story.
Software version 1.29 is not compatible with this BIOS version.
I've read other reports of problems with this version.
I am now using version 1.40, which performed very well in all tests.

[goldenfireblue]

Re: HP probook 640 g2 - does it self destruct with bios chip removal?

So did we determine that the bios has some kind of tamper proof. My problem is I backed it up with v.1.14 and since thats not compatible. I don't have anything to go back to. I've using V1.40 now but none of the bios dumps I use work. The computer won't turn on, just the charging light blinks.

[goldenfireblue]

Re: HP probook 640 g2 - does it self destruct with bios chip removal?

I solved it. The ram module was the problem, so my backups could have been fine all along. I ended up using the bios dump with ME region cleared. Is there steps I need to do to populate that region?

[SallowDay]

Re: HP probook 640 g2 - does it self destruct with bios chip removal?

Almost a year later, I tried my hand at salvaging it again once more.

Although flashrom reads and writes to the bios chip just fine, the laptop won't boot. In fact, it acts precisely the same way it does without a bios chip in it at all (when plugged in, the charge icon flashes, and it will not turn on).

I followed this gentleman's steps to a tee, by the way: https://www.youtube.com/watch?v=vgbWtxv_hqM

I also used a .bin I got from badcaps, which I attach here.

Can anyone think of what I might be doing wrong? I'm truly stumped. When I tried this a year ago, I thought my flash might have been bad since my Pi's power source was a little bit iffy, but I've one with no issue now, and nothing has changed...