This worked for me with 890 Pro as well with just one small addition. When doing the firmware updates, I had to do them while in safe mode in order to correctly pair everything.

Also be sure to update the firmware, even if it says you have the latest version.

Safe mode for RF Extender - Unplug RF extender power and USB. Hold connect while you plug extender into the USB Cable. Keep holding down connect until the RF light begins to flash (up to 30 seconds or so). Let go of connect. The RF light and the Status light should now be blinking alternately.

Safe mode for Remote - Take the battery out of the remote, hold down
the "Off" button while you plug the USB cable in. "Safe Mode Requested" will show up on the screen. Let go of Off button.