Changing display output
With current kernel version (4.13) changing display output must be done by recompiling u-boot. This is necessary because kernel supports only SimpleFB. This will change in the future.
Create blacklist file:
# echo "blacklist sun4i_gpadc_iio" > /etc/modprobe.d/blacklist-touchscreen.conf
# echo "blacklist sun4i_gpadc" >> /etc/modprobe.d/blacklist-touchscreen.conf