No service after firmware upgrade on huawei e1820 mobile modem ?

Hi!

I recently upgraded the firmware on my e1820 huawei mobile modem. After this has been done, the modem couldn't get any service anymore .. I didn't realise that upgrading firmware would mess everything up.

SIM is on the 3(three.ie) network, in Ireland and it looks like it doesn't get signal from the network now.

Any suggestions on how to get the service back ? Any link for a good firmware that works with three Ireland? thanks