su sekilde bir cozumu var ben denedim oldu:
*#36951#
put 2 chips on cell
Disable WLAN.
1-enter in factory mode *#3646633# or *#36951# or *#9646633#
2-go to RF Test Tool
3-choose GSM, confirm OK!
4-go to Power scan
5-Select Band DCS1800 click OK
6-the cell frozen
7-wait for 3 minutes testing
8-while testing connect to a pc using the USB cable (do NOT select ANY of the options appearing on the cell screen)
9-Click the CENTER button of the cell until you go back to principal menu
10-go to settings/network settings and choose GSM Preferred or any other option (except WLAN only!!)
In this way the cell does not reboot, and the wifi application stays off, so the option can now be changed...