Clock resetting had nothing to do with the hack.
All GH2 cameras have an small internal battery just for keeping the date/time constantly set to proper value. It gets charged by the main battery and when fully charged (24hrs of keeping the main battery in the camera body) it should be capable of saving the proper time for 90 days, even when the main battery is removed. Your internal battery seems to be out of order and should be replaced.
If your camera is still under guarantee, Panasonic service in your country will replace it for free.
It was the internal battery and it was fixed under warranty - very hazzle free by the way :-)
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