Very late to this but I had this same question back in May and Roku support said this “I am sorry to inform you that Roku remote can only be connected to TV for volume and power access. It cannot be used to control a projector.”
Hoping they add support soon. It’s a major miss!
Using CEC doesn't require "pairing". CEC simply works if the two devices are compatible.
IR doesn't "pair" either. You simply program in the correct codes for the TV being used. No Roku remote can be IR configured to control anything but a TV unless by some coincidence another device uses the same IR codes as a supported TV.
I was able to pair my Roku remote successfully. I can Power On/Off , Volume +,- and Mute my Nebula Projector. Go to “Setup Remote for TV Control.” I chose the CEC Setup option. I tried typing in “PROJECTOR” under TV model. That brought up a few tv options, but something told me to try “HKPRO” and it worked! Hopefully that helps you out. Good luck!
Using CEC doesn't require "pairing". CEC simply works if the two devices are compatible.
IR doesn't "pair" either. You simply program in the correct codes for the TV being used. No Roku remote can be IR configured to control anything but a TV unless by some coincidence another device uses the same IR codes as a supported TV.