16.06 Linux release for DragonBoard 410c

Hello,ndec:
I have update the bootloader and I use the rootfs:linaro-jessie-alip-qcom-snapdragon-arm64-20160630-110.img.I only make the kernel and generate the boot.img again.I refer to the official document to execute it,but when I programming them,every thing is Ok.But I can’t rmmod my driver after I insmod it.So if I want to insmod driver again,I have to shutdown and restart the system,What the reason about it?