Hello ! i’ve got grey (not blue or red) 5800 bought in april 2009. Curently it has firmware 21.0.025 (when i’ve got this phone it has ver.20) updated through Nokia Software Update. So there is one annoying problem. About one time a day, or may be in 2 days phone suddenly reboots when some action occurs. For example: – when i recieve SMS, not just recieve – when i’m pressing button "Show" (or whatever it named) – when i’m using GPS software and go to player (remember that 1 time) – or like today even when i was reading a book and screen was auto rotated when im turn the phone – or some other action i cannot remember Anyway. This stuff never occurs when phone is just lying on a table, even if it playing some music and doing some other stuff at the same time. It happens when you click something or switch to other app or recieve a call or sms. You need to do some action. And you cannot just try to force this stuff to happen. It will open 10 sms and on 11th it will reboot. It happens by itselfs suddenly (as i say not very often, but 1 time in about 1-2 days). In 8 times of 10 it will just reboots and will not asking pincode – just nokia wellcome screen and then it goes to desktop. But sometimes it will ask pin. It was happenning since i’ve bought the phone. At that time there was not any additional soft installed. I thought it was bug in firmare but when i’ve updated to ver.21 thus bug doesn’t go away. so…. does any body knows what is this and what i need to do ???