Hello,
At the first time,
sorry for my english
So i have the same probleme for reinstalation Ubuntn upon BQM10 FHD. J've arrived succesefuly
I arrived successfully to install in proceeding by this steps:
My BQ is connected upon my computer
My BQ is shoot down
I boot it in recovery mode in pushing OFF/ON and Volume up in the same time
So BQ is in recovery mode
I starte UBports installer and the installation go normaly.
I have a logo of ubuntu in the screen and after 5 minutes of silence... I boot in the word of linux.
Et voila !