@creuzdos
Did you try with dev mode on in uTouch then with adb shell?

And alternatively i just saw an other thread that could help you with terminal inside uTouch.
I'll quote here :

@craig said in How to install PIA VPN on UT (Working!):

When running the script, you may get a message that the script was not able to write to /etc/openvpn. If so, do this before you execute the script:

sudo -i sudo mount -o remount,rw / sudo chmod 777 /etc/openvpn exit

After you run the script, set permission back:

sudo chmod 755 /etc/openvpn

You could try the chmod 777 with \system folder.