ERROR* UVD not responding, trying to reset the VCPU!

Seems the issue related to Radeon graphic driver. You need to edit the Grub file.

Option-1: If Ubuntu is able to boot:

1. sudo nano /etc/default/grub
2. Change the line GRUB_CMDLINE_LINUX="" to GRUB_CMDLINE_LINUX="radeon.modeset=0" or, GRUB_CMDLINE_LINUX="nomodeset" and Save the file
3. sudo update-grub && sudo systemctl reboot

Option-2: If Ubuntu is not able to boot:

1. To edit Grub during the boot, do the following:
2. Immediately after the BIOS splash screen during boot, press and hold the SHIFT button. This will display you grub containing a list of kernels and recovery options
3. Press e to edit the kernel
4. Find the line ending with quiet splash. Add your boot option before these key words - i.e. so the line looks like nomodeset quiet splash
5. ctrl+x to boot

It should work now. Also remember, if you want to permanently use nomodeset, then, after boot, follow my Option-1.