Please add your own experiences, including how to replicate the issue and whether you found a workaround; perhaps this will be of help to us 5310 early adopters.
Bugs (as of version 3.60):
1. Random reboots while playing music. Seems to be a common one, some people have mentioned playing lower bitrate songs solves the issue. Here's a good thread on this:
5310 : 2 problems2. Dead volume keys. Haven't personally experienced it but its documented in the mentioned thread above.
3. Random reboots while using camera with high resolution settings. I tried lowering the resolution, didn't seem to help. It usually happens while the camera is saving a picture after taking it; the phone screen goes white, the interface restarts, and the stored image is corrupt and not viewable.
If you look at this and the music player problem from a coding perspective, it looks like a memory leak; I'm guessing S40 handles it by simply restarting the UI, but I know nothing about the inner workings of S40 so take it + a grain of salt.
4. Random reboots when using enhancements. The phone has done this on a few of occasions, what seems to trigger it is connecting/disconnecting enhancements while on a call. This includes the included stereo headset, and a BH-800 bluetooth headset.
5. Intermittent bluetooth connection. Sometimes the phone just decides to drop the connection to my BH-800 headset. It happened to me while on a call; nothing was audible on neither the headset nor the phone, it took a few seconds after manually switching off the headset for audio to resume on the phone's ear piece.
If I try to reconnect to the accessory through the bluetooth menu, the phone gives an error saying it can't; the only fix is to power-cycle the phone.
6. Network name is not always shown on the top left; I tried everything, but eventually it started appearing when I added an email account with auto-checking and the little '@' symbol appeared on the top. Go figure.
7. Low ringtone/alert tone volume, even on the highest setting.