Lucky sod, their config software is up their with printer driver install software from the late 90s 
These aren't presented in a list you can select from, you have to type in what you've got (model numbers work great, generic descriptions not so much), and then it suggests it's nearest match.
This is my device list, with the new one on the right, in case it helps anyone in future.
As long as it'll recognise all the button presses now i should be able to re-map what i need. Cheers for the help.
use the Microsoft Media Center Remote profile
I saw that suggestions a few times, but MyHarmony won't find that, it keeps matching it to 'Media Center PC [Microsoft Windows Media Center]'. Is that what you mean?
I take it I can keep the old MCE Keyboard one too, as it'll let me map buttons to keys (particularly t, y, and o) that aren't showing up under the Media Center PC one?
Config as in the topic. I subbed the RasPi in for a HTPC that's awaiting replacement parts. All look fine, but I've no cursor/direction/arrow keys working.
The Harmony is configured as per: HOW TO - Configure a Logitech Harmony Remote for Kodi
It works fine if i plug this IR receiver into any other machine and use this remote.
I tried adding it through the keymap editor but it wasn't detecting the presses. They are getting sent as the IR receiver is old enough to have a red flash when it receives input, but whatever it's sending for the arrows isn't getting picked up.
ir-keytable output (in case that's helpful):
LibreELEC:~ # ir-keytable
Found /sys/class/rc/rc0/ (/dev/input/event4) with:
Name: Media Center Ed. eHome Infrared Remote Transceiver (0471:0815)
Driver: mceusb, table: rc-rc6-mce
lirc device: /dev/lirc0
Supported protocols: lirc rc-5 rc-5-sz jvc sony nec sanyo mce_kbd rc-6 sharp xmp imon rc-mm
Enabled protocols: lirc nec rc-6
bus: 3, vendor/product: 0471:0815, version: 0x0000
Repeat delay = 500 ms, repeat period = 125 ms
Anyone any ideas?
