New Display in 17t-cn000 boots to W11 fine, but NO image when booted to UEFI CMOS Settings

[justdaveTX]

>Bizarre Issue - brand new and correct HD+ 1600x900 Brightview display screen from reputable Seller installed in HP 17t-cn000. Laptop boots to pre-existing fully-up-to-date Windows 11 PRO... but screen shows NO image at-all when booting to UEFI CMOS Settings, via ESC > F10.   [When 'stuck' in there, blind, "can" force a reboot using CTRL+ALT+DEL, and laptop then does boot to W11 Login Screen et al normally.]  Several other display replacements from same Seller have all worked well.

>Have tried attaching External Monitor via HDMI port, and that display ALSO is blank when laptop is booted into UEFI, and ALSO works normally when booting laptop into W11.

*FYI,  i have repaired over 10,000 computers, literally, in my 35+ years doing this work for Clients. THIS issue i have never seen before, and i have seen some real doozies!

[justdaveTX]

>Further details: tried "bcdedit /set {globalsettings} highestmode on" - to force the UEFI firmware to use the highest GPU resolution which UEFI 'exposes' during boot... and tried "bcdedit /set {global settings} graphicsresolution 1600x900".  SAME.

>From within W11, downloaded and installed last-available F.29A UEFI update/utility... ran it with Admin privileges, and it

successfully auto-rebooted, flashed the new Firmware in, and auto-rebooted to W11.  But SAME no-images before Login.

>Removed Disks and both SODIMMs and Main Battery (modern laptops have no 3V RTC backup coincell anymore; which means some Exec received a Bonus that year for that dumb cost-saver decision)... held the 'Power-button' down 62 seconds... put in 1 known-good 8GB DDR4 module... and attempted boot to ESC>F10. SAME blank screen.

>To remove W11 completely from the 'equation' (recall the huge Microsoft Corporate hack, then the CrowdStrike mess??)...

prepped a HDD with correct GPT partitions, with correct GUIDs (in another laptop running a "real" OS: GNU/Linux).

>Booted the laptop to "MINT" OS on USB-attached FlashDrive... the UEFI checked the Signature as it should (SecureBoot was enabled by HP), then DID boot to the OS on FlashDrive. *It's activity LED flashed. NOTE: the HDD was-not-yet connected.

>Waited 8 seconds for MINT to get to a later stage (HW detection), THEN connected the HDD's SATA connector. MINT OS came fully up within 30 seconds, and the HDD and it's partitions were detected fine (examined in Gparted).

>Installed MINT OS (a distribution of GNU/Linux that has an 'appearance' most-like Windows, which some Clients prefer), and

Restarted it ==> the laptop DID reboot to the fully-functional/installed OS on the HDD... BUT the screen still shows NO images

'during' boot (no HP logo, no Mint logo one would normally see)... and NO images when attempting ESC>F10 for UEFI access.

>Next steps: 1 -  try a NEW Display Cable (least expense)... 2 - try another NEW Screen Replacement from different Vendor.

[Irfan_06]

Hi @justdaveTX,

Welcome to the HP Support Community.

Thank you for posting your query. I will be glad to assist you.

I see that there is an issue with the laptop hardware and may need repair.

The support on the HP community is currently available within certain constraints. We are striving to enhance our assistance and broaden its scope. We appreciate your understanding and patience.

I've sent you a private message with the instructions. In order to access your private messages, Click the Private message icon on the upper right corner of your HP Community profile Next, to your profile Name, you should see a little blue envelope, please click on it or simply click on this link

Take care and have a good day.

Irwin6

HP Support