A few hours of forum-crawling got me the very first release of firmware version 1.4 for Panasonic Lumix G1, which permits the use of 3rd party batteries. I have installed it successfully on my parallel imported Japanese version and have been using 3rd party batteries since. I have uploaded it to a file-sharing site to save you people some time, please note that it has not been tested on the English version or any other, download and use at your own risk.
Download from HERE.
by WuJo
