I would suggest firstly running the ‘Check disc for defects’ option first to ensure the write was perfect (maybe I’m just unlucky, but I have failures semi-regularly with this stage regardless of what box I use)
Did you try “Start Lubuntu (safe graphics)”? I would hope it would boot there, which would allow you to use ubuntu-bug
to submit a bug report (by far the best way, on the hardware with the issue). The two get linked automatically if you add a bug number into the bug area on iso.qa.ubuntu.com test results.
Launchpad is used as normal for bug reporting, the ISO QA tracker is used for additional tracking on who & when it was discovered (with which daily image etc useful to pinpoint when issues occur for regressions etc).
I’ll provide http://iso.qa.ubuntu.com/qatracker/milestones/410/builds/207267/testcases/1301/results which shows some examples of what I did for some fails with the 18.04.4 image. It also shows another entry by @kc2bez who had a successful test. (FYI: there was no reason why I chose that date, it was just the first I found)
FYI: I have a text file which contains the ~17 boxes I use for QA testing, I made up my descriptions in the format is “brand model (cpu, ram, gpu)” by using data provided by lshw
. I just copy the appropriate boxes line from that file into the comment line when I start a test …