Finally I got my bq aquaris E4.5 updated to UBports. On Gentoo. Actually it was not so hard at the end. I gave a try to magic-device-tool, disabled debian packaging related stuff in the script, downloaded ubuntu-device-flash package and extracted ubuntu-device-flash binary from it, changed path in the script accordingly, and voila, my phone is up to date. Also, I have used magic-device-tool to back up my data first.
Anyway, you do not have to use magic-device-tool for those operations, just follow Ubuntu Touch web page. And, for example, use rsync for backup over the wi-fi to your computer, or run it locally on the phone to copy the data to SD card.
If you have any
questions regarding this, feel free to contact me at my e-mail address.
Copyright (c) 2018 PAVUK