IR910 works wonderfully with LORIOT and I'm sure Vit knows that too, but I guess the original question was about using an IR910 with LoRa on TTN. I'm also looking for this option as I have one lying around and TTN's own LoRa gateway is taking longer than anticipated.
The 910 runs a stripped down version of Linux so there is quite a significant amount of work to make it totally compatible with TTN. It has to be build outside the IR910, using the Semtech drivers as provided by Cisco, and the compiled package can be installed on the IR910.
Unfortunately I don't have the time to work on this but I'm happy to give access to an IR910 with LoRa card (868) to whoever is interested.