I didn't know you can flash kernels through recovery !
I only knew via PC...
I see. Thank all for correcting me. Could you please give me the download link for stock kernal .ftf
If you want just to revert back to full stock you could also try repairing your phone with SEUS
---------- Post added at 06:56 PM ---------- Previous post was at 06:34 PM ----------
I also found this thread.
It gives all (I am not sure if all) the stock firmwares for Xperia SP.