[Q] How to return to stock kernel? topic

So I returned my Galaxy S4 (SGH-1337M) to stock through Odin today because I have to send it in for repair. The only problem I have is that when the device reboots, the "Kernel Is Not Seandroid Enforcing, Set Warranty Bit: Kernel" message shows up in the top left hand corner. I'm pretty sure that Samsung won't repair my phone if they see that, and was wondering how can I return to the stock kernel? Thanks.