USB 3.0 Boot on Elitebook Folio 9470m

Hi,

I often need to boot off of a USB drive on this laptop and I've been using a generic USB 2.0 drive for a while but my new Transcend 32gb JetFlash 820 is not being recognised as a boot disc at all.

I've updated my bios to the latest version (F.48) but I'm still having no luck.

Any help would be appreciated.