No need to lump everything into one pile. This topic is only about GPIO manipulation. You already have another topic for modem related issues.
If your SIM card becomes accessible with a certain value set (1?), then you need to add the following to /etc/rc.local before exit line:
echo 525 > /sys/class/gpio/export
echo out > /sys/class/gpio/gpio525/direction
echo 1 > /sys/class/gpio/gpio525/value