HP Elitebook 820 G4 BIOS repair assistance required

[Wutru]

Hi guys,

If someone would be able to provide some expertise, I'd be very grateful.

BIOS Corruption - Cause
So I managed to corrupt my machine by installing linux and enrolling custom secure boot keys. I did choose to enroll the Microsoft keys as well, to prevent any potential bricking due to 3rd party drivers from HP being signed with those keys.
After doing that, and rebooting(it did boot, powerLED, fanspin etc.), the laptop did not give any video output on the LCD or video connectors. I think I was able to get in BIOS and trigger the beeper by pressing ESC. So the BIOS was not corrupt but at least no video out.

EliteDesk Repair
I had this exact same situation happen to me (because then I did *not* include the MSFT keys) on a HP EliteDesk 800 G2 DM, which I managed to repair by desoldering the SPI ROM and replacing the BIOS region with UEFITool 0.28 with a fresh BIOS region extracted from an HP update executable- That is all I had to do.
Their behaviour was fully shared between the Elitebook and Elitedesk, no video, but able to get in BIOS and trigger beeping with Esc or F10.

My tools:
- CH341A (3.3V modification)
- EZP2023+
- UEFITool A78 (latest I think)
- UEFITool 0.28

Elitebook Repair
Because of this earlier success, I went straight ahead with this machine. Desoldered the ROM, dumped it and replaced the BIOS region, and resolder it.
Then it had the following behaviour:

1. When connecting power (battery or ext. power), the charging LED flashed white/amber (white/orange) for a few seconds.
   1. This would indicate, according to the 820 G4 Maintenance and Service Guide (page 70): "The embedded controller is recovering the boot block or DXE. Since it takes 10 sec. or so to load the DXE image and get video in the DXE case, this blink code is necessary. (SureStart)"
2. Then it went off for a few seconds, and then the charging LED came back on solid amber/orange, either with or without battery present.
3. But the machine would not start up, no power LED, no fan spin nothing.
4. Removing the power, holding the power button, windows + B, or other button combinations etc. all did not work.
5. When reconnecting the power, I experienced the same as step #2 & step #3.

I then went ahead and removed the board from the case and disconnected the CMOS battery from a few minutes. The behaviour changed:

1. A lot more LEDs(I think WiFi, charging and power) came on, and stayed on.
2. The Power LED came on when pressed, and after a few seconds the fan started spinning up to max speed
3. Still no video.

I have backup of the original dump, (triple verified before reprogramming anything) and the repaired BIOS. There is a separate 64MBit EC ROM and the Embedded controller is a Nuvoton NPCE586HA0MX.

Any help will be greatly appreciated.

[hoaca388]

Hi guys,

If someone would be able to provide some expertise, I'd be very grateful.

BIOS Corruption - Cause
So I managed to corrupt my machine by installing linux and enrolling custom secure boot keys. I did choose to enroll the Microsoft keys as well, to prevent any potential bricking due to 3rd party drivers from HP being signed with those keys.
After doing that, and rebooting(it did boot, powerLED, fanspin etc.), the laptop did not give any video output on the LCD or video connectors. I think I was able to get in BIOS and trigger the beeper by pressing ESC. So the BIOS was not corrupt but at least no video out.

EliteDesk Repair
I had this exact same situation happen to me (because then I did *not* include the MSFT keys) on a HP EliteDesk 800 G2 DM, which I managed to repair by desoldering the SPI ROM and replacing the BIOS region with UEFITool 0.28 with a fresh BIOS region extracted from an HP update executable- That is all I had to do.
Their behaviour was fully shared between the Elitebook and Elitedesk, no video, but able to get in BIOS and trigger beeping with Esc or F10.

My tools:
- CH341A (3.3V modification)
- EZP2023+
- UEFITool A78 (latest I think)
- UEFITool 0.28

Elitebook Repair
Because of this earlier success, I went straight ahead with this machine. Desoldered the ROM, dumped it and replaced the BIOS region, and resolder it.
Then it had the following behaviour:

1. When connecting power (battery or ext. power), the charging LED flashed white/amber (white/orange) for a few seconds.
   1. This would indicate, according to the 820 G4 Maintenance and Service Guide (page 70): "The embedded controller is recovering the boot block or DXE. Since it takes 10 sec. or so to load the DXE image and get video in the DXE case, this blink code is necessary. (SureStart)"
2. Then it went off for a few seconds, and then the charging LED came back on solid amber/orange, either with or without battery present.
3. But the machine would not start up, no power LED, no fan spin nothing.
4. Removing the power, holding the power button, windows + B, or other button combinations etc. all did not work.
5. When reconnecting the power, I experienced the same as step #2 & step #3.

I then went ahead and removed the board from the case and disconnected the CMOS battery from a few minutes. The behaviour changed:

1. A lot more LEDs(I think WiFi, charging and power) came on, and stayed on.
2. The Power LED came on when pressed, and after a few seconds the fan started spinning up to max speed
3. Still no video.

I have backup of the original dump, (triple verified before reprogramming anything) and the repaired BIOS. There is a separate 64MBit EC ROM and the Embedded controller is a Nuvoton NPCE586HA0MX.

Any help will be greatly appreciated.

You MUST:

• Read BIOS guides, methods, resources and tools
• Try the method at BIOS guides, methods, resources and tools before requesting help
• Explain you were not able to succeed with the methods at BIOS guides, methods, resources and tools
• Use search function in case someone already answered your request
• Post under a related thread if it exists
• Provide the full machine model number, serial number (or Service tag, SNID) and the board model number (see https://www.badcaps.net/forum/showthread.php?t=88758 ) ,The serial number, make, full model number, motherboard model and revision (except QR codes) must be written/typed at your request as per the rules. Not as a picture, part of the file name and so on.
• Name your thread with make, full model numbers and request
• Provide a BIOS/EC dump if possible
• Attach files directly to your post instead of linking to external websites
• Post what the problem is, be specific - black screen, no boot, running slow, password. Do NOT post "clean me", "clear bios", "clean bios", "fix bios", "bios need" or other such terms

[Wutru]

Hi hoaca388, thank you for your reply, please see my answers in italic below:

(list of points)

You MUST:

• Read BIOS guides, methods, resources and tools
  • I have read this (very well written) guide and used it up to get to this point where I get stuck
• Try the method at BIOS guides, methods, resources and tools before requesting help
  • I have tried the methods in this (very well written) guide and used it up to get to this point
• Explain you were not able to succeed with the methods at BIOS guides, methods, resources and tools
  • I have succeeded with the methods in that (very well written) guide on another machine, the EliteDesk 800 G2 DM
  • But the EliteBook 820 G4 does not succeed as it behaves differently
• Use search function in case someone already answered your request
  • I have used the search function extensively, but it is difficult to find threads only related to elitebook G4 models. It appears the search function ignores the G4 part
  • I have seen similar threads but they usually include CAPS Lock LED blinking or other symptons and totally different hardware models
• Post under a related thread if it exists
  • I did not find sufficiently related threads to an HP Elitebook G4 (820/840/850) discussing problems (all I could find were just bios dump or repair requests) so I decided to open a thread
• Provide the full machine model number, serial number (or Service tag, SNID) and the board model number (see https://www.badcaps.net/forum/showthread.php?t=88758 ) ,The serial number, make, full model number, motherboard model and revision (except QR codes) must be written/typed at your request as per the rules. Not as a picture, part of the file name and so on.
  • Product Number: Z2V91ET#ABH
  • Serial: 5CG8210XWC
  • GbE: 10:62:E5:4F:8A:96
• Name your thread with make, full model numbers and request
  • I think I did this
• Provide a BIOS/EC dump if possible
• Attach files directly to your post instead of linking to external websites
  • See attached zip file with my dumps in this post
  • I have included:
    • Original dump
    • clean HP BIOS extract
    • my repaired BIOS by replacing BIOS region with UEFITool 0.28
  • I am hesitant to desolder the EC because it is surrounded by 0402 SMD resistors
• Post what the problem is, be specific - black screen, no boot, running slow, password. Do NOT post "clean me", "clear bios", "clean bios", "fix bios", "bios need" or other such terms
  • When connecting power (battery or ext. power), the charging LED flashes white/amber (white/orange) for a few seconds.
    1. This would indicate, according to the 820 G4 Maintenance and Service Guide (page 70): "The embedded controller is recovering the boot block or DXE. Since it takes 10 sec. or so to load the DXE image and get video in the DXE case, this blink code is necessary. (SureStart)"
  • Then it goes off for a few seconds, and now the Power, charging and WLAN LED turn on, the power button LED turns on, and after a few seconds the fan starts spinning to max speed
  • No video, black screen

[hoaca388]

Hi hoaca388, thank you for your reply, please see my answers in italic below:

You MUST:

• Read BIOS guides, methods, resources and tools
  • I have read this (very well written) guide and used it up to get to this point where I get stuck
• Try the method at BIOS guides, methods, resources and tools before requesting help
  • I have tried the methods in this (very well written) guide and used it up to get to this point
• Explain you were not able to succeed with the methods at BIOS guides, methods, resources and tools
  • I have succeeded with the methods in that (very well written) guide on another machine, the EliteDesk 800 G2 DM
  • But the EliteBook 820 G4 does not succeed as it behaves differently
• Use search function in case someone already answered your request
  • I have used the search function extensively, but it is difficult to find threads only related to elitebook G4 models. It appears the search function ignores the G4 part
  • I have seen similar threads but they usually include CAPS Lock LED blinking or other symptons and totally different hardware models
• Post under a related thread if it exists
  • I did not find sufficiently related threads to an HP Elitebook G4 (820/840/850) discussing problems (all I could find were just bios dump or repair requests) so I decided to open a thread
• Provide the full machine model number, serial number (or Service tag, SNID) and the board model number (see https://www.badcaps.net/forum/showthread.php?t=88758 ) ,The serial number, make, full model number, motherboard model and revision (except QR codes) must be written/typed at your request as per the rules. Not as a picture, part of the file name and so on.
  • Product Number: Z2V91ET#ABH
  • Serial: 5CG8210XWC
  • GbE: 10:62:E5:4F:8A:96
• Name your thread with make, full model numbers and request
  • I think I did this
• Provide a BIOS/EC dump if possible
• Attach files directly to your post instead of linking to external websites
  • See attached zip file with my dumps in this post
  • I have included:
    • Original dump
    • clean HP BIOS extract
    • my repaired BIOS by replacing BIOS region with UEFITool 0.28
  • I am hesitant to desolder the EC because it is surrounded by 0402 SMD resistors
• Post what the problem is, be specific - black screen, no boot, running slow, password. Do NOT post "clean me", "clear bios", "clean bios", "fix bios", "bios need" or other such terms
  • When connecting power (battery or ext. power), the charging LED flashes white/amber (white/orange) for a few seconds.
    1. This would indicate, according to the 820 G4 Maintenance and Service Guide (page 70): "The embedded controller is recovering the boot block or DXE. Since it takes 10 sec. or so to load the DXE image and get video in the DXE case, this blink code is necessary. (SureStart)"
  • Then it goes off for a few seconds, and now the Power, charging and WLAN LED turn on, the power button LED turns on, and after a few seconds the fan starts spinning to max speed
  • No video, black screen

HP EliteBook 820 G4 Notebook PC

[Wutru]

Thank you. Sadly, no improvements are noticed.
I have included a dump of the EC.

[hoaca388]

Thank you. Sadly, no improvements are noticed.
I have included a dump of the EC.

New EC

[Wutru]

Thank you. No improvements however - charging LED keeps blinking, with an extremely short blip of the power LED.
Managed to fan spin once, but it went to max speed. No video or even impression of backlight turning on.
Now it just it won't fanspin even and keeps at white/orange blinking

I don't know how to proceed. I would not suspect hardware issues because the computer worked fine initially until I rebooted it after setting custom Secure Boot keys in Linux