I have flashed (Vanilla + Combined) my "recent" N900 yesterday and installed CSSU-thumb.
I also installed a few (stable) applications, none of which having anything to do with internet connection or phone calls...

Of note: I use only cellular connection, no wifi at all.


Everything was rather smooth and working as intended, but then I made a phone call, and notice it cuts the internet connection off.
So after the call I tried to re-establish my connection, but now it's asking me if I want to allow data roaming.
If I say no, then no internet connection for me (whereas I could browse and download at will prior to making that call)...

It's an issue I have initially when I got the phone, and that's the main reason I did a full reflash.


Are those normal behavior ?
- Phone calls cutting the (cellular) internet connection
- Data roaming being needed afterwards

What can be done to squash those pesky problems ?

well phone calls cutting internet connection is normal behavior and all phones does this but i never faced anything about roaming. with my N900 when i end the call my data connection gets established again automatically.

At first it asked me if I wanted to automatically switch data roaming on, which I obviously denied.
Now of course everything it detects a tentative connection to the internet, it asks for data roaming, and when denied again... as expected nothing happens.

That's highly frustrating and infuriating, not to be in control of what's going on.

Could it be some kind of deal between two operators? Here in the UK we had such a deal between Orange and T-Mobile (now under a joint name EE), whereby one would provide coverage in blind spots of the other. The phone may recognize it as roaming. Just speculating...

Internet and phone calls hmm I don't know I think I had an issue when put the modem to gsm or 3g the best was for me dual mode.
You played with that also? Did you connect to a good network with full speed?

pichlo and halftux already pointed out the most probable reasons.

Call ending inet connection is absolutely normal behaviour on 2G (whereas on 3G it should not be).
And those roaming: you are not living close to any border? Then it is obvious. If not, then pichlos explanation could match here. We had something here in Germany with O2 and T-D1, but as it was MCC (country code) phone should not ask 'allow roaming' and never heard like that (but who knows about our N900 SW in such details?).

I'm always in dual, and it was getting 3G when it got cut off as I made that call.

I'm nowhere near a border, and while my operator (Free Mobile) is using another's (Orange) infrastructure, there is no switch between them: it's always Free.

What is quite odd is that I made that call at home: before the call everything was fine and I could connect to internet to my heart's content, and right after I "recovered" from the call: data roaming all over.

My phone was originally from Vodafone but when I switched to 3, it would not allow me to connect without allowing data roaming. As far as I know, this isn't a problem unless you go abroad, it won't connect to another network in your home country. I think vodafone and 3 share certain masts. When playing flappy bird, it often says vodafone. I'd put it down to an n900 quirk.