Odyssey X86J4105 unable to load bios

Just received my Odyssey X86J4105 with 64GB eMMC. Trying to boot to bios by plugging in a keyboard and holding down delete key. Device does not boot in this situation. Tried 2 keyboards and all the USB ports without success. Booting normally goes to windows 10 without problems, and the keyboard works fine.

Any suggestions on how to get to bios? Any way to do it other than via delete key?

RFM
F7 as described in the manual

Apologies, didn’t mention that I used F7 first up after reading manual. Wont boot to bios with F7 either. I resorted to delete key after trawling through all the online documentation that seems to mostly recommend it.