I haven't tested all the different file systems, but it appears that it is possible to boot from only FAT(16) and FAT32 file systems in UEFI boot mode on USB flash drives on my new Dell Inspiron 7567. I spent about half an hour trying to figure out why Windows wasn't installing in UEFI mode, until I realised the laptop's BIOS was booting the drive in legacy boot mode.

Could we please make it possible to boot from NTFS-formatted drives in future BIOS revisions, given that this has been the standard with most other manufacturers for a number of years?  And yes, this does matter to those of us wishing to put files >4GB on their USB boot drive. BIOS revision of the Dell is the latest at this time (v1.2.0). Thank you.