It's been just two days since Sony announced that it's developing phones to run Mozilla's new Firefox OS, but the Japanese manufacturer has already released an experimental ROM for its Xperia E smartphone. The Xperia E is an ultra low-end Android handset that matches the "Keon" developer device almost spec-for-spec, which makes it a good fit for Mozilla's new web-based OS.

Today's announcement is yet another indication that Sony is loosening up and improving its attitude towards the development community. Of course, Sony's not completely relaxed about users doing what they want with their devices: the Firefox OS ROM comes with the now-familiar warnings that unlocking your bootloader and switching operating systems "may void your warranty." If you understand the risks and want to try out the ROM, head over to Sony's developer portal for the download and installation instructions.