I have a problem when I connect the mobile Internet, it connects, but when I use it, drops the connection. I've done tests putting the SIM card on another device and the other connects usually just does not work in N900. Already flash the firmware with maemo flasher, but to no avail. Have tested other SIM cards and all connected normally, the only one that does not work, that stopped working is the "Brazil Telecom". Please help me.