There just no crontab at all in firmware, and no space for additional software, i don't understand why they  used 256 mb flash , and left for /config only 20 mb, so we are limited to 20 mb firmware size.
And you simply can't control fan speed, also there is no possibility to change voltage, you must raise/lower input voltage to overclock/downclock. I'm kinda expert in s5
Maybe i can rebuild u-boot and change partition layout, but i need beaglebone black for experiments, and don't have money to buy them