Root .42 & Update to .62 OTA
If u want to update OTA ........
a) Your Boot loader should not be unlocked (Default setting by Sony Ericsson)
b) Root your phone which is running on .42 firmware using the latest Flashtools v 0.6.8
Note :
i.First install Flash tool.
ii.Connect the phone in Flash Mode
iii.Flash it with 4.0.2.A.0.42
iv.Turn on the phone when flashing complete
v.Connect the phone with usb debbuging enabled.
vi.Open the Flashtool
vii.Then press the lock icon on flashtool.
viii.Phone will automatically reeboot after done
c) After rooting update your phone OTA
You can try using Wifi/3G/Edge