I was trying to install on a Dell Inspiron 3558 Laptop i3-6001U with Intel HD Graphics 5500. It was a black friday deal, and I figured I could make a portable setup for Recalbox and play it on any TV. I returned that laptop and found another.
The new laptop (HP ProBook 430 G3 (i5/HD520) which did boot from 32GB USB, but it doesn't support SD boot, which is a bummer. At least it booted though, so I guess this is/was some sort of hardware problem with the Dell, as stated.