kernel development Xperia

Xperia M2 D2306
Android: 4.2.2
Bootloader Unlocked: Yes

Development kernel with linux mint & Windows 8.1
I gained some knowledge about android much as modifications and scripts that perform specific actions

Using OS Linux Mint eh I could decompile the boot.img file


I had access to the script can be seen from root explorer in the path: /

But investigating more thoroughly about modifications cpu frequencies are situated on the zImage file

The question is how descompile the zImage?
some tutorial

Now as if there will be an issue that can continue to decompile the kernel when the same can now add the root with its binary respective


thank you for your help