Problems after upgrade to Ubuntu 20.04LTS

After do-release-update -d after startx I see Nvidia label and after this don’t start GUI. But I see console with UBUNTU 20.04. Also kernel don`t upgrade to 5.4. How I can upgrade kernel and save video driver?

Try this to fix the no GUI issue:

Edit GDM custom configuration settings: (If it exists)

sudo nano /etc/gdm3/custom.conf

once you open this file, remove the # from # WaylandEnable=false
save and close the file & reboot. I’ve had to deal with this issue many times. Its Ubuntu breaking the NVidia drivers its a known bug & was fixed after 18.04.

Hopefully, this helps you.
I don’t think they have a kernel yet for it. Hopefully soon.

This line haven’t # in my case(

Xorg.conf have a # in line with driver name and it was a problem. Next step is update kernel to 5.4, becouse kernel don’t upgrade after upgrade ubuntu

Try from ssh if you can connect :
export DISPLAY =:0
With xrandr you can what modes you TV/monitor has supported .
Maybe some regresion or broken with compatibility Resolution or hz detected incorrectly.

xrandr --output HDMI-0 --mode 1920x1080 --rate 60

Change HDMI-0 to DisplayPort if you are using DisplayPort
Change the resolution for you resolution returned by xrandr compatibility
Change rate hz Will be helped.

I have sometimes had problems getting 4K 60hz and I have to limit it to 4K 30hz for it to work.or Switch to 1080p 60fps

Well if you figure out how to upgrade the kernel, please share that info.