I downloaded the 20.04 ISO this morning and ran into a number of problems trying to install it on my multi-boot PC.

Trial 1: Full package set, download updates, install vendor content, XFS for root partition, mount existing /home partition => install failed almost immediately after clicking the install button on the last setup screen with error ubi-usersetup failed with exit code 141.

Trial 2: Full package set, no updates, install vendor content, XFS for root partition => install completed, but failed to boot up to a login screen after restart.

Trial 3: Full package set, download updates, no vendor content, XFS for root partition => install failed to complete; opening up the details dialog it looked like it was stuck in a slow loop.

Trial 4: Full package set, no updates, no vendor content, XFS for root partition => install completed and successfully booted up to a login screen after restart.

The 20.04 installer appears to need some more work.