I understand how to pair devices, guerby. I've not had any trouble with ANY pairings except the N800 with SU-8W, and that's been consistent between two separate setups. Not sure why. I spent a great deal of time looking into it but gave up when it became obvious the experience was too flaky and random to easily diagnose.

The Fn key behaved very strangely on both keyboards tested. The indicator light would only stay lit if the button was pressed within a very narrow, specific time window-- not too early or too late. I can understand "too late", but the early part is mystifying. Anyway, trial and error got it to work, and I'm moving on.

Texrat, surprising. Did you pair and use successfully your SU-8W with another device?

someone with working bluetooth keyboard can write here the output of this cat:
$ cat /var/lib/bluetooth/BT_MAC/classes | grep KEYB_MAC
$ cat /var/lib/bluetooth/BT_MAC/features | grep KEYB_MAC