мне когда то помогло вот это....правда модель была просто u600
- Download last S/W version (Use version name as of U600**GD4 ~ ).
-Input Keystring *#9998*86824# to adjust TouchKey sensor level.
(The time required will take nearly 20 second.)
If succesful, you can see message "TOUCHKEY DOWNLOAD COMPLETE!".
- Make sure to power off/on(Reboot) when upgrade completed.
- In order to check download success, Input keystring *#0206*8376263# and confirm TouchVer : 1.3 or over