Originally Posted by samwathegreat
Hmm, I've never used a custom Kernel, but boot.img contains the Kernel. I bet that is your issue. You should be able to download the SBF for your carrier, extract "Boot.img", and fastboot flash it.
I suggest making a backup first, just in case something goes awry.
Let us know if that does the trick.
Lol, thanks mate. I did extract the boot.img some days back from the ROM and I flashed it via Fastboot, everything went fine and I even got the stock kernel back, but WiFi would not turn on, and without WiFi I can't do this test. I guess something is missing from the boot.img file, something else needs to be flashed as well, just don't know what.
I am giving up. I will format the phone when 4.4.4 will be released and that time I will check if Screen Mirroring works or not, it should, just for the peace of mind, then I will have to flash custom kernel and then it will stop working again.