Precision 3640 No USB Boot Option

Just got a new DELL PC and there is no boot from USB option. I've scoured this forum for previous solutions but they don't work for this. Did DELL finally disable all external drive booting? Is there no way around this? I'm using a flash drive install created with Windows 10 Media Creation Tool.

I've posted some pics so you can see the settings I changed to try and allow USB booting. I also checked the "Enable USB Boot Support" box in the BIOS (not shown here) but no dice...