The EM6ULL default support SSH. Please refer to ssh.pdf for details.

Yes.

Use the follow command to view the gpio base:
# cd /sys/class/gpio
# for i in gpiochip* ; do echo `cat $i/label`: `cat $i/base` ; done
Then execute follow command to use GPIO.
#OUT_IO_NUMBER=3
#echo ${OUT_IO_NUMBER} > /sys/class/gpio/export
#echo "out" > /sys/class/gpio/gpio${OUT_IO_NUMBER}/direction
or #echo "in" > /sys/class/gpio/gpio${OUT_IO_NUMBER}/direction
#echo 1 > /sys/class/gpio/gpio${OUT_IO_NUMBER}/value
or #echo 0 > /sys/class/gpio/gpio${OUT_IO_NUMBER}/value

For example: 800 x 600 modify to 480 x 272 . User only need to modify kernel file "imx6ul-14x14-evk.dts".

Execute the follow command to start recalibrate touch screen.
#cd etc
#rm pointercal.xinput
#reboot