The sound not working in Windows after BIOS update (in HP service)

[Ulibrk]

I got the Notebook from HP service with BIOS updated to version F.26 - the sound in Windows 10 64 does not work.

The symptoms:

• Realtek Speaker nor Headphones produce any sound. Silence.
• Everything else seems good - the volume can be changed, the headphones plugged in are detected, microphone graphic bar detects sound input.
• Bluetooth speaker works.
• The external audio device (Scarlett 2i2) works.
• UEFI Audio test works.
• Boot from Linux Ubuntu live USB - sound works.
• Full PC reset and clean installation of Windows 10 was performed, fully updated, HP assistant troubleshooting performed, and all drivers updated - no sound.
• In the audio control panel - Speaker - Properties - Advanced, the error jumps out - Test tone failed (or similar) - Windows 10
• Updated to Windows 11 - no sound.
• In the audio control panel - Speaker - Properties - Advanced, the window stops responding and cannot be closed (other than Ctrl+Alt+Del way) - Windows 11
• Performed a clean install of Windows 11 - no sound.
• Win+B startup and BIOS restore performed, but version F.26 was restored.
• Windows 11 clean install performed again - NO SOUND!

Summarization:

After the BIOS update, onboard audio does not work in Windows 10 and 11. Almost no signs of problems except the silence.

Could I get the BIOS downgrade file, at least?! I do not have time to put it in service again and wait for 3 weeks for an unexpected result.  Also, the warranty has expired in the meantime.

Nothing can be downloaded for my notebook. https://support.hp.com/us-en/drivers/selfservice/hp-envy-15-ed0000-x360-convertible-laptop-pc-series...

It looks everything is working against me. Fortunately, my company payed for the computer. But I can asure you, that I will buy or request from my employer HP computer never again.

Thank you.

[Ulibrk · Accepted solution]

I was able to solve this in the end. I had to use a Live USB drive created on another computer using MediaCreationTool downloaded from Microsoft to create a full clean install of Windows 10. Then the sound finally starts to come out from the speakers.

I suppose this could save someone`s time. Also, reverting the BIOS to F.24 was not possible because HP does not allow this, although the file was on the disk in the end. But there was some message about the missing signature file. To revert BIOS to the previous version, which has a backup on the device, the HP requires some signature file. As I said previously, I am done with HP.