I'm running a cf-root, SG SII with KL1 kernel and cyanogenmod 7. Before getting it done the way it is now, I went through several failed attempts. I'm afraid the first few times I installed the wrong kernel because the blue progressbar didn't appear, the phone rebooted and then the screen gradually lit up, showing pixels of different colours scattered all over, like a sort of gradient. It was very frightening, therefore I ask: has the "pixels" thing done any damage to my phone, in any way? Have the wireless/gsm antennas been affected by this incident? (I've read, although I didn't really understand, that installing the wrong kernel can affect I a way -- again, didn't get in which way-- your wireless antenna's performance) Is this the truth? I've experienced difficulties when connecting to some wifi networks. Also, a firend's Galaxy Note showed more wifi bars than mine, of the same hotspot. Does that mean I have a problem? Would be "flasing a new radio" the solution? Thank you!
You shouldn't be able to damage your hardware through software. It's obviously not impossible, there are things that control voltages and so on, but in general it's not even worth considering.
The Note and the SGS II have different hardware and software; there's no reason to believe that the difference in bars you see is anything other than normal. If your connection has a problem, you'll notice when you try to use it. Don't rely on the bars.