HP Elitedesk 800 G2 DM / Mini -> Can't get BIOS flashed, tried multiple. Update Brick

[Datahoarder]

HP EliteDesk 800 G2 MINI/DM (1L PC)

I have 40 of these units. All of which i tried to update bios with HP's utility got bricked. All of them were bios password locked, i used the jumper thing to reset it. Couple updated bios, one of which worked fine for _ONE_ boot. Second is now mixed with rest, i don't know which it is specifically so have not retested it.

All had some MESpilock failed errors on (my) first boot of the unit.

Photo: https://cdn.discordapp.com/attachmen...018_220853.jpg

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I have CH341a programmer with which i've been banging my head to the wall for ~15hrs of the past 24hrs.

Now finally i got to a place where i could properly get the BIOS written with CH341a programmer V1.31 -- this is the first one which would pass verify, and multiple times, even after resetting the programmer (replugging).

I tried to boot, and it was in forever boot loop no post, power consumption did not raise high enough. Felt like memory training failed.
Some biosses cause power consumption to be ~8W and CPU fan slowly ramps up, nothing else (normal boot should peak above 30W).

Programming original BIOS i got from one of the working units fails too.

I tried the 3.3V mod, verified, re-verified and re-verified, it worked, but at that point could not detect the IC at all. I have now reversed it (well V3 still gets 3.3V but VCC 5V) and this is first time i've gotten verifiable the bios written correctly in there.

I have not desoldered, and use the SOIC clips. Fiddly but i'm confident i get them hooked correctly. Pin 4<>Pin 8 resistance is somewhere along the lines of ~4.6k OHM, so should be fine to flash without desoldering.

Most of these have Winbond W25Q128FVSQ some have an MXL chip in them.

I need the latest BIOS for NVMe compatibility issues, but could live with just restoring the dead units (now 4) to functioning state.

Attached is one bios i got copied verifiably out.

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Could anyone help me get these working, esp with latest bios? But i'll take anything at this point.

Once that is done, i'd like to take a look too at what we can edit with uefitool etc. could the FAN curve be changed via the EC chip for example?

[hoaca388]

Re: HP Elitedesk 800 G2 DM / Mini -&gt; Can't get BIOS flashed, tried multiple. Update B

Why you don't remove CMOS battery and and I see you don't have a voltage lowering board for CH341A

[Datahoarder]

Re: HP Elitedesk 800 G2 DM / Mini -&gt; Can't get BIOS flashed, tried multiple. Update B

Why you don't remove CMOS battery and and I see you don't have a voltage lowering board for CH341A

CMOS battery good point. Also i made the voltage lowering mod as well, then couldn't do anything at all on these.

Further testing revealed that every read of the bios was DIFFERENT.

So i'm suspecting my programmer may have been faulty. I bought several new of those CH341a and some more expensive unit but haven't had time to test yet.

[reeluff]

That CH341 voltage "mod" creates more problems, I would leave it as is.

However, if you have 40 units to program, do yourself a favour and get a T48 programmer - you will be in pain running at the speed of the CH341.

Unfortunately, you will be best to remove the bios chip from the mainboard - normally creates more problems leaving it on the board, especially as you say every read is different.