I have had this problem for months, driving me absolutely mad. I found the only way i could fix it was to leave it turned on and sit it ontop of a wireless router for a min or 2. Have been searching the intertron for ages, was about to give up and buy a new device, but the slapping trick truley did fix it. I couldnt belive it. for anyone else who has the problem, dont think its silly, it realy does fix it.
JB