HID Proxy (a long shot)

[Lantizia]

This is a long shot but thought I'd ask.

We've got a couple of K810's paired with D-Link DBT-120 bluetooth dongles. These dongles can run alternate firmware which enables HID Proxy mode. In essence our PC's don't see our K810's as bluetooth keyboards, but rather as USB ones via the DBT-120 dongles (and the OS doesn't even realise they are bluetooth dongles - not unless you run the hid2hci utility to swap it back).

We do this because it makes rebooting between OS's (and accessing the BIOS) a dream as there are no worries about pairing... and you can take the keyboard (with dongle) "to go" for other machines - kind of like a Logitech Unifying Receiver.

Is it likely that the k81x-fkeys utility can be used still given this? I'm getting the impression it just sends a magic sequence and it probably doesn't matter if it's a USB HID device or a Bluetooth one? Not had any luck just yet though...

p.s. Does anyone else find (irrespective of this utility) that the multimedia keys (on F5 to F12) do not function in the slightest on Linux? (I'm on Ubuntu MATE 18.04 personally)... I've read this may be something to do with keycodes higher than 255 but things like evtest/xev don't even recognize you've pushed any key (tried in HID proxy mode, tried in bluetooth mode using both the D-Link DBT-120 and also my laptops built in bluetooth).