I got a replacement 622 on Monday, activated it and it was working fine. I got home on Tuesday and unit was stuck in a rebooting loop. I unplugged it, then plugged it back in and it does it searching for sats test and as soon as its done, it reboots again? Is there anything I can do before I call tech support? Is there a way to force the original firmware back on and start with a "fresh" start?