Comment 3 for bug 1596097

Please note that rc and rc-proposed are two different channels. You can read about Ubuntu image channels here:
https://developer.ubuntu.com/en/phone/devices/image-channels/
On the following link, you can find a detailed instructions on switching the channel (the answer by Jens Grivolla):
http://askubuntu.com/questions/764554/how-to-change-from-ubuntu-touch-stable-channel-to-rc-proposed
The instructions are exactly for bq M10. But mind the channel -- they are for switching to rc, not rc-proposed.