Jiayu released new firmware for G3 to fix standby power consumption problems. Firmware version is: G3-20121129-082828
Firmware files are different for the different upgrade methods:
For SP Flash tool download from here
For CWM to update using SD card, download here
Download links are in Chinese. Click on the white button on the right side on the page opened. Don't forget to rename the files after downloading to avoid problems.