Upgrading to the latest and greatest is a cool thing. I thought that myself after I saw the new screen of the latest Ubuntu release floating on Reddit. Yesterday I started my computer and it proposes me to upgrade form Ubuntu 19.04 to 19.10. I was simply "why not?" and started the process. The upgrade went as expected in the background while I was using my PC. Once in was done (it took probably about an hour) it requested a reboot, but the fun stops here as the OS has not responded after arriving to the splash screen.
Note: I hope this solution helps you. I am running Ubuntu on an PC with an AMD processor and UEFI/SecureBoot but this might also apply to other configurations.
I didn't planned to spend my weekend on fixing my PC, but here I was siting next to it with my phone googeling for similar issues. I found similar issues for earlier releases, but nothing helped. I wanted to read the log output on startup hoping to find something out, but it was not displaying anything. Also I tried to switch another tty without any success, as the splash screen simply stuck on the animation.
I do got a blimp of hope after starting and pressing the esc key and got some logs. At this point sometimes I managed to go to pass the splash screen ad login, but sometimes I only got some logs and the splash screen was completely frozen (also the animation). At this point I looked for a solution to stop the splash screen, as this looked pretty promising.
In order to do this I rebooted and made sure to get to the grub loader (you need to press the esc key after the boot device has been selected).
By pressing E you can edit the boot configuration.
At this point you can change the startup from quiet splash to nosplash in order to skip the splash screen on start.
The configuration can be saved using ctrl+x and at this point the operating system will boot using the newly provided configuration.
I was able now to start without randomly pressing esc (if you made it until this point and managed to login you are good to go). There is only one step left, the changes done above is only temporary and it needs to be done after each restart. To avoid it a change in the grub configuration is required. This can be done using sudo nano /etc/default/grub and setting GRUB_CMDLINE_LINUX_DEFAULT to nosplash:
After saving the file use sudo update-grub2 to update the boot entry.
