I have an Xperia Z c6603. Getting H+ over ATT networks at 850 MHz.
ATT in my home area only offers H+ at 1900 MHz.
I get no H+ in my home area, since the c6603 does not use the 1900 MHz frequency.
The c6602 works with 850 and 1900 MHZ.
I understand the c6603 and the c6602 have exactly the same hardware.
With that, I believe my phone is hardware capable of both, 850 and 1900 MHz, but not programmed for it.
I have flashed c6602 firmware on my c6603.
The model number on info screens still shows up as c6603.
I still do not get H+ with the c6602 firmware.
QUESTION: Is there any way that I can completely transform my c6603 into a c6602 so I can access 1900 MHz in my home area?
Put differently, since the hardware is exactly the same, I assume it's the programming that activates certain frequencies. Some threads say the modem needs to be "enabled" for these frequencies, which is more than a simple baseband or firmware flash. My c6603 did not work well with c6602 baseband flash. I'd like full compatibility, hence my question about full transformation of a c6603 into a c6602.
Any help would be greatly appreciated!