I used the JK4 modem up until the JVO release Continuum that I flashed last week. Worked just as well as it did in 2.2. You do need to be mindful of how you flash it, as there is a 2.5 and 3.0 CWM flashable zip, as well as the tar file. If you flash it with CWM, you need to make sure you have the correct version for your version of CWM. If you use Odin and the tar, no worries.
I flashed it and it seems to have taken care of the problem. ThanksI'll second the jk4, I flashed it after flashing serendipity 7 and it cleared up a lot of issues I was having.
