Really strange that it seems that wlan0 is locked. As you have mentioned before, I also thought that the pineapple is a device with 2 unlocked radio's, as they have marketed. Maybe there was a heat issue when the txpower was above 18dBm,so it is now locked somehow in the software. I think we have to wait till someone explains why the txpower is maximized to 18dBm. I guess there's a good reasons for it. but then again do not advertise it. I have already spent to much time on the txpower now instead of on the real fun stuff which can be done with the pineapple. It still is a great device.