Hmmm, that is not the problem what is is that i dont understand the instruction on ihacker, this one in particural
Skip to the Last Step if you are already on Firmware - 14.3.A.0.757.
Install Kernel.ftf for C6903 (.757) or Kernel.ftf for C6902 (.757) with Flashtool to get compatible Kernel and Baseband.
Reboot and Enjoy.
I dont have a 757 firmware flashed on my phone, so should i flash it first, then fastboot ihacker kernel then proceed with install and at the end install this kernel.ftf for my 903 ? Or just without 757 fastboot kernel, and just at the end flash this kernel.ftf ? All of this gets kinda confusing sometimes to get my head around