HP EliteDesk 800 G6 mini - BIOS Chip (GD25B127DSIG) replacement after epic fail :D

[Berun]

Hello All,

I tried to read the the BIOs chip(GD25B127DSIG) on the mainbord of an HP EliteDesk 800 G6 mini, because the BIOs had an Admin Lock and I got the "HP Endpoint Security Problem" Screen at every startup which is not very useful when I want to use the PC as a Compute Unit for my home media system somewhere in the cellar, so it should perform a restart without any interactions.

I only have the CH341APro Programmer available and did the 3V hardware Mod on it before I tried to read the BIOS chip.

I read the Chip on board 8 times (with power connected on without, with and without RAM installed ...) but every time I compared two consecutive reads they where not identical.

So I though lets unsolder the chip and read it directly. And of cause after successful desolder and fiddling with the chip clamp one leg of the Chip broke off .

So now I ordered a new BIOS Chip (GD25B127DSIG SOP8) and I am sure that I have to program it before I solder it in.
But I can imagine that there are some information which are device specific, right?

The device I bought used on Ebay is :
HP EliteDesk 800 G6 Desktop Mini PC
Serial No. 8CC3161TTL
Product No. 349A6EC#ABD

I read in another Thread that someone did the BIOS unlock with RCUnlocker but he still needed a second try to get rid of the "HP Endpoint Security" screen issue, would be nice to get rid of this in one step so I do not need to maybe unsolder the Chip again

Here a Picture of my Epic Fail :



Please help me understand:
-what I need to flash to the new chip
-will it also fix the Endpoint Security issue or do I need to perform a second step?

Thanks a lot for your help in advance

BR

Berun

EDIT: At first I thought that i should post in BIOS requests, but then I read the rules of that sub-forum and thought it would not fit, now I have read more threads in the Bios sub-forum and no think it might be better there ... So i want to apologize to the forum admins for maybe having put the threat into the wrong sub forum.

[Berun]

Quick update on my progress and what I have learned so far:

The inconsistent reads I got initially were clearly caused by using the SOIC clip in-circuit. After reading more into it , it seems the board (PCH / EC / power rails) interferes with the SPI bus, so the dumps were basically unreliable , the board was even blinking an error code while the reader was connected so definitely something was awake on the board while doing so.

In the meantime I gathered some more info and analysed my 8 different dumps:

• I was able to recover my original serial from the inconsistent multiple reads:
  SN: 8CC3161TTL
• I found a clean/unlocked BIOS dump (S21, version 02.25.00) for this exact model here in the forum.
  (HP EliteDesk 800 G6 DM) "g6 Help HP Elitedesk 800 G6 Mini PC LOCKED BIOS elitedesk ec file locked _unlocked.rar"

From what I checked so far:

• BIOS version matches latest HP release
• ME region is present and looks sane
• Image structure seems valid (no obvious corruption)

So my current plan is:

1. Program the new GD25B127DSIG chip with that unlocked dump with my CH321APro with 3V Mod.
2. Solder it back and test boot
3. Check if the "Endpoint Security Controller (ESC)" issue is gone , additional info about that below.
4. Restore DMI data (Serial + Product) using NbDmiFit
5. Optionally run HP BIOS update once from Windows afterwards

My current understanding is:

• HP BIOS update tools only update the BIOS region, not the full SPI flash
• So they will not fix deeper issues (like ESC problems) if those are outside the BIOS region
• the dump i found could work because they reset NVRAM / security state, but requires full flash via Programmer what I am forced to do anyways.

If anyone sees a flaw in this plan or has experience specifically with the ESC issue on this model, I would really appreciate your input — especially if this can be fixed in one flash and not require a second round of desoldering😄

I will most likely open another thread in the BIOS sub-forum to get a suitable "verified" BIOS Dump candidate that hopefully fits in the first try, I really want to avoid to unsolder again.

Tanks again for all the info in this forum, it helped a lot already.

BR
Berun

[Berun]

Update: Flash did work and I could start the PC, SN number is wrong but the BIOS is unlocked. ESC error persists but at least I can set it to just a info and 15 sec start delay, so remote restart will work.

Will see that I get the correctly edited BIOS and a fix for the ECS issue in the other SUB Forum.

BR

Berun