I installed Manjaro ARM KDE version using etcher on microSD card. It seems the OS loaded but I couldn't get display working. I only have old monitors, so I have to use HDMI to VGA converter.

I had used ayufan and mrfixit image and the display was working perfectly after I lower the resolution via extlinux.conf. In Manjaro, I also tried to set the resolution lower via setenv video-mode and bootargs but no luck. I didn't forget to run mkscr, too.

Its a pain as they are hit and miss the ones with usb power input are better as sometimes not enough power is supplied.
Boot unplug vga and connect back straight away when you are expecting output.
Prob is sometimes it can send the video to bad resolution or have the monitor at the wrong res.
Those cheap hdmi to vga convertors vary very much in quality.
The Armbian images are really bad for it but Manjaro works with mine.

It was working with the same hardware on ayufan. The SSH server is up but I don't know the password. user and pass manjaro didn't work!

EDIT: too bad I can't install VNC server, because Strit says somewhere in other thread that there is no default password.

Some do Manjaro is trying to stay totally mainline whilst Ayufan provides specific fixes for a specific image.
Looks like the defonfig compile and default setup doesn't like your hdmi adapter.
I am the same with Armbian and those HDMI adapters are not great and do vary in quality as have had 3 now.
Wish I didn't sell the U-green one I had as that was the best of the lot and just got some cheap ones from ebay but actually they are a real mixed bag.
One useless and another not so bad but doen't like Armbian like I say.