allwinner a33 tablet factory reset when i try to root

i am trying to root my a33 tablet (multilaser M9 quad core ml02), kingo root works succefully, but when i reboot the tablet it factory resets with no reason (but keep the root because root modifies the system partition), and then every time I turn the tablet on it reboots from factory, after the root the only thing i can do to make it stop from factory reseting is reflash the factory firmware and lose the root.

is there any protection system that must be disabled ?, is it a bug ?, how can i make it be rooted without reseting every time ?, is there a way to debug the boot process to know what makes the tablet reset ?