@alainw94
****s://www.skyneel.com/how-to-fix-nvram-error-in-all-mediatek-devices
I use this on my M10fhd to fix wifi losing password.
maybe you could search this website for ideas.

How about reflashing the original ,it came with, as behind Ubuntu is Android which controls the screen - if I am wrong ,I am sure someone will correct me.
Trying to give you some ideas, as it is holiday time ,and the usual experienced guys ,may not be available.

Have you searched BQ forums ?

will BQ support help you with this, my guess is that this is in the android side of things .
can you use flash-tool to go back to android , see if you can sort the touch screen, ""or it may automatically fix it "" then restore UB.

@advocatux
my apologies,sorry

https://www.amazon.com/Motorola-S10-HD-Bluetooth-Stereo-Headphones/dp/B004QWOSLK/

i use these, but shop around they are usually about 20. usd
as they are an old design ,the link is just so you can see them

Ebay 2 sets for, 21usd

@cioccoblocco
it is usually because you are not getting an ADB connection.
before you connect to pc, put your device in developer mode, connect while still on this screen,look for a small window on the device ,asking to ALLOW connections, if you dont see it ,try ,in terminal "sudo adb devices".
then try ,ubports installer from there ,or
reboot to fastboot manually when the installer asks for it

@randomuser
device
stable /RC / DEV.
might help ,those that know ,to help you

@marathon2422
guess we should have read the info on the app upgrade

@domubpkm
same on my Pro 5