Using Ubuntu-Mate 16.04.02 with Raspberry Pi 3. After doing Rpi-Update to the latest kernel it cannot boot up with NO Signal on HDMI Since rpi-update kernel 4.19.115+ to 5.4.42-v7+.
Have to revert back rpi-update kernel 4.19.114-V7+.
See Post methods to revert back to rpi-update kernel 4.18.114-V7+.