HDMI output stopped working

Hello,
I have an Asus TH101A with intel HD graphics from Atom X5-Z8350 CPU.

My HDMI otuput is not working anymore. I know it's not a faulty hardware because I tested it on a linux live USB.

I tested 3 drivers. One from ASUS (version 20.19.15.4364), one from windows update (20.19.15.4444) and one from Intel (20.19.15.5171). The first two are 2016 drivers, the last one 2020.
HDMI output do not work with these drivers, and with the one from intel the display is turned 90°

Could you help me ?
Thanks

There's a setting in the Intel HD Graphics Control panel that lets you toggle between landscape mode and portrait mode. But part of the window is off-screen, i.e., you can't see this particular setting because it is positioned outside the screen's borders. The trick, then, is to move the window in such a particular way that the part of it that shows you this setting becomes visible. This can very easily be done by using the keyboard as described in this article:
How can I move a dialog/window using just the keyboard? | IT Pro

That could solve the landscape mode with the intel driver, but the issue is HDMI output does not work even with this one.
None of them work.

In that case it could be that the screen resolution, that it automagically detects and switches to immediately the first time when you hook up the display device to the HDMI output port, is incompatible with the display device's hardware specs. I actually keep an old version of TeamViewer portable for this one purpose, as it lets me see where I need to click to change the display resolution to the one that does work. With later versions the TeamViewer window would just go blank as soon as I plugged the HDMI cable in. Should you decide to try it like this, then be advised that older versions of TeamViewer had a security hole in them, but you won't be affected by it if you set it to allow only LAN connections. I have tried multiple other methods before, but none of those ever seemed to work. The old version of TeamViewer portable that I have been using for this is 10.0.45471.

No it does not detect anything. When I plug in the HDMI cable, nothing happen, I still have display on my primary screen.
I can go to display settings (intel tool, or windows settigns) and I can see no other screens are detected.

Weird. Have you tried futzing around with the various settings like the ones under Windows Settings | System | Display

• Multiple displays
• Advanced display settings

?

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Also please keep in mind that, to be able to achieve a full reset of a HDMI connection, you need to unplug the HDMI cable on both ends of the cable before plugging either end back in. Does it work when running on Windows if you hook the Asus up to a different HDMI display device? Maybe you could try to remember what exactly it was that you changed about your setup just before it stopped working?

Yes I checked these settings. I also tried to disconnect both ends of the cable, and different devices.
I think what changed was some windows updates but I could not say which one or when exactly.

If you have verified that the HDMI cable is not faulty, i.e. it starts working again, repeatably, each time as soon as you boot into the Linux Live CD, then the only thing that I know of that might help you troubleshoot this is to do a clean boot, which is to disable all drivers excepting only the ones from Microsoft, and, next, try enabling them again one by one to narrow down the ones that might be the culprit. Or if that doesn't help either, then resort to backing up whatever important data you might have stored on there and do a clean install of Windows 10 to rule all the other variables out of the final equation.

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I am assuming you already tried the sfc /scannow command from a command window to let it scan for corrupted system files, followed by the dism /online /cleanup-image /restorehealth command if it found errors that it couldn't fix, and that you also already tried to Repair Install Windows 10 with an In-place Upgrade

I have been able to make it work ONCE only :
Clean install windows 10, remove automatically installed graphics drivers, install ASUS drivers.
But after reboot it does not work anymore, even though ASUS drivers are still in use

Seems like the driver has serious issues. I would get in touch with Asus support team first, and then maybe also Intel Community forum website, but the latter often results in a typical-old "you bought it from Asus, so you need to contact Asus" kind of response.