Which version do you have?
I have 2.6.32.9-ga42712e running rubix focused 1.0
You're still on the 2.3.15 (OTA) kernel, the above referenced update method should work. Just make a nandroid backup to be safe. Follow the instructions in that link and you should be set.
Still read the post made by that maderstcok guy, petty sure it first installs .320 then reinitializes the system and installs .340 all in one clockwork install. So it should update .15 as well. Again verify that first or you will have to sbf back to stock .15 and then take the ota to get current.