I have updated over network the Raspbian on my Pi Zero. Attached a Bluetooth dongle, same as in some tutorials, halfcircle barely wider than USB port. The dongle works OK as network connection to a mobile phone BT shared network. So the dongle should be out of the suspects list.
It is a bluetooth keyboard, Gembird KB-BT-001 has problems connecting. It has the ESC+Q command for pairing, but sometimes it pairs without even completing the pairing session from computer side, sometimes it just continues blinking and no connection is established. It never connects as per the book.
When it appears connected as in paired without the pairing action, it sometimes works partly - only the blue symbols as for the FN function key was pressed. Once it worked almost entirely, just not the P key, which has P and blue minus on the physical keyboard, but when pressing the kay it gave the star *, suggesting different layout. I cannot replicate same behaviour, as it no more works that way. Now the most I can get is the blue symbols as for the FN Numlock mode. Feels somehow inconsistent. And here comes the punchline.
It works same inconsistent way on my main Computer, which doesn't have Debian as on Raspi Zero, but Lubuntu instead.
And the last uppercut comes from trying to use it on my third coputer, which has generic Ubuntu, with all the bells and whistles of Unity and stuff. There it works always perfectly. The only difference is Unity vs LXDE and one meter placement towards west. Little bit less cable clutter than my main PC and Raspi place infront of it. All the installed packages are the same as on my main PC, have tried all possible combinations of them on my main PC and almost all on the Raspi.
What is the solution to that? I doubt a little the possibility of interference from cables, as the standards for electronics producers are pretty tight, and there is no special wiring going on here, just consumer electronics. I have actually no ground wire, just phase and zero for may main 220V line here in house, which have given some problems for my washing machine, but that seems to me as pretty far fetched reasons. Probably just getting a bit desperate :D
Few days later. Seems I have two problems, one is sorted out. Got connecting and pairing straightened by using bluetoothctl via ssh and following commands in it: [bluetooth]# agent on [bluetooth]# default-agent [bluetooth]# scan on Esc+Q [bluetooth]# connect 09:30:DE:20:00:00 Connection successful [CHG] Device 09:30:DE:20:00:00 Connected: yes Request PIN code [agent] Enter PIN code: 12345 [CHG] Device 09:30:DE:20:00:00 Paired: yes First it works for all keys, except numpad letters, numbers types there. After Fn+NumLock only the numbers with Fn key work. Not possible to switch back.
I have opened the keyboard. The heart of it is Broadcom BCM20730, Bluetooth 3.0 single-chip HID. Compliant to Bluetooth Core Specification versions 1.1, 1.2, 2.0 + EDR, 2.1 + EDR, 3.0 + HS and 4.0. I cannot find any firmware to reflash it, as I suppose the fault is in the keyboard. Support just gives default answers and point to the place of sale for eventual repair.
A day later again. Got one step further. When I have another (full, with real numpad, PS2) keyboard attached and press Numlock on that twice, it changes the BT keyboard mode and I can type letters again. When I press Numlock twice again, it changes to only keypad again. First time once, all next times twice, also the BT Numlock. Weird, and still not solved, as it is too easy to accidentally press Numlock and then another keyboard is required anyway.
Weirdly enough I can't anymore replicate it working normally on the Ubuntu Unity system. Tried in Virtualbox Windows 7 and same now consistent way of first normal and after first Numlock press unlockable modes.