Comment # 18 on bug 1164737 from Walter Zimmer

No Problem, I'm happy to know that nomodeset saves me from getting into the
basement to pull out my old monitor when I'll install the final 15.2. :)

Anything else I can do? Already the installed system from 15.1 boots without
nomodeset, so in general the support for this monitor is working since some
time - just not in the 15.1/15.2 installer. So it seems the answer to the
riddle is hidden in the xorg.0.log from the case where it's aborting. Maybe
I'll try that NFS logging again... or maybe just plain to a USB stick?