Not as far as I can tell from the manual; it says "If your product stays connected to the network, every-time you turn off the product it will search for any updates available onMore speculation, maybe even wild. Some Humaxes (eg. 1800/2000T) wake up every flippin' day (04:30 I think) to do a software search, even though there is no OTA software anymore. I haven't found a way to stop this. Does the 4000/5000 do this? If so, at what time? Unlikely, but it could be one possibility for the device being on.