The installer cannot start as the graphics card is not supported. The result is that you get dropped into the text-based installer which does not work.
This is kind of disappointing as this is a very light laptop that supports up to 32 GB RAM, which would be very nice to have with Qubes.
I forgot to include the actual specs for the machine I used for testing:
Intel(R) Core(TM) i7-7600U CPU @ 2.80GHz
16 GB RAM
Intel Integrated HD Graphics 620
Specs at: http://www.dell.com/sg/business/p/latitude-14-7480-laptop/pd
Thank you. Doing that allowed me to do a normal install. However, the resulting installation does not have working networking (neither wired nor wireless). Doing "ip link" does not show any physical devices, so I suspect that this is a driver issue.
I will build a new installer image in the hope that it will contain the appropriate drivers. I will update this post when this is done.