[Xperia Mini ST15i] no 3G icon and cannot connect via mobile internet
I have an Xperia Mini st15i.
The problem is that the phone never shows the E,3G,H icons,
and cannot connect to mobile internet.
(via wifi it works ok).
Initially the phone had the Android 2.3.4 firmware.
The initial update to firmware 4.0.4 build 431 was done using the phone itself.
I had read somewhere that this way,
some problem might occur during the update via the phone
and this causes the 3g,etc icons not to appear
And they suggested to re-flash the phone to build 587, doing a factory reset.
That's why I have (successfully) flashed it from build 431 to ST15i_4.1.B.0.587_Unbranded.ftf using flashtool.
(I've also checked the option during the flashing, to "Reset customizations"=factory reset).
But, it didn't help
The internet settings in the device are ok, I've doublechecked them manually.
And, in Settings>About phone>Status, it shows indeed 3G.
(and generally, the 3G signal here is strong: other phones in the house, using the same or other carriers, all show 3G or Η icon all the time)
I've tried putting other SIMs (of the same or other carrier) in the phone, but didn't work.
What do you suggest?