[Q] Flash only the kernel?

[moto.defy]

Hello everybody,

is there any chance to flash only the kernel? If that could be done, we could flash the 3.5 kernel on a Fire Phone with fire OS 3.6.2. Then use towelroot and flash back the 3.6.2 kernel. And we will have a rooted fireOS 3.6.2.

Please let me know if it is possible!

Thank you!