Hey folks! Reviving an old thread here. This is still a serious bug, I don't quite understand how this topic could become so old though...

Anyway, just as my pre-poster stated, I have reason to assume that FasterN9 causes these connection issues.
I tried it several times now:

Having FasterN9 installed, the mobile internet connection gets lost randomly (as far as I can tell, I didn't notice any special conditions) and it's not possible to get it back (neither flight mode circling, nor switching network mode, nor anything else in the settings works) instead of a reboot, which is incredibly annoying if you want to work productively. Plus, rebooting eats out a massive percentage of your battery charge for some reason.

Having FasterN9 NOT installed, the behaviour is just as normal as you would wish it from your device. 2G/3G connection is stable, you can change network to wifi and back, no problem. :-)

I don't really remember when this bug happend to appear for me, but it may just be in time with me trying FasterN9 out. I will definitely miss my speedy N9 without this optimization :-(, but I'd rather have a stable connection than a speedy phone, that's just the way it is...

Just for your information: I am from Germany, using an E-Plus SIM.

This did the trick for me, anyone else made this experience?