I have the same problem as what was mentioned in the posts. My reboot is taking 12 hours.
I just got off the phone with Philips' tech support (1-888-486-6272) and they do not know anything about this. I asked if anyone else has reported this problem and they said no.
I am concerned that if they do not know about this then it won't be addressed in the next version of the firmware.
Perhaps those of us with the problem should call Philips and formally register the problem so that they can start working on it.
They said that there should be a way to control the frequency with with the iPronto is updated with the EPG data. I know that it is not a solution but at least a way to reduce the occurance of the problem.
They couldn't tell me how to do it though.