This works perfectly with LibreELEC.
1. Change the channel on the remote
Press 'setup¹' until 'OK' blinks. The blinks show the current channel.(4 blinks means channel 4). Now enter the new channel (1-16) and confirm with 'setup'.
2. Change the channel in LibreELEC
In a linux shell (bc² installed)
echo "65535 - 2 ^ X" | bc
Or use a calculator
X is the channel.
e.g.
Channel 1: 65533
Channel 2: 65531
Channel 3: 65527
Channel 4: 65519
Channel 5: 65503
Channel 6: 65471
...
You will need this number for the driver.
The next part is a small script for LibreELEC that unloads the driver and reloads it with the necessary channel (channel_mask). If you already have a autostart.sh, just add the modprobe lines.
echo "#!/bin/sh" > /storage/.config/autostart.sh
echo "modprobe -r ati_remote" >> /storage/.config/autostart.sh
echo "modprobe ati_remote channel_mask=65527 mouse=no" >> /storage/.config/autostart.sh
chmod +x /storage/.config/autostart.sh
¹ button with the globe
² bc is the 'Basic Calculator'