Originally Posted by widu13
Kernel version: 3.0.15-I9100PXXLPH-CL378510dpi@DELL128 #3
I say think as I obviously can't check now! Unless it's elsewhere?
I can find no trace of that kernel for the O2U, "P", variant.
Basically, I think you have flashed a CF-Root kernel that does not correspond to your original kernel which would explain not being able to boot up. Since I cannot be sure of your phone's original kernel at this stage, I think it would be best if you flashed your stock Samsung, "P" variant, firmware to your phone, using Odin. This would return you to the stage you were at prior to your attempted root and once you are up and running you can ascertain exactly what the stock kernel is so that you can root your phone.
From your post, you are on the, "P", variant firmware which you can download to your PC from here
You can then flash this firmware, which includes the stock kernel, using Odin and following the instructions here
in post #1, under the heading, "My firmware is not eligible for ICS yet but I want it now!