The Sony X10 was the first Sony phone to have Android as the OS. When it released two years ago it was highly anticipated for having a sleek, sexy, modern design (it’s still a great phone to look at compared to more modern devices), but the software was the device’s ugly side. The Sony overlay on Android was slow, crowded, bloated and did I mention slow? Worst of all there was no support from Sony so that developers could modify the phone, sure they’re very helpful now, but that was due to the huge backlash of complaints for the X10. Well the device is still getting some love from the developers over at XDA.
A couple of developers have been working on getting the stock ROM of the Xperia S onto the X10, they claim that many of the bugs and kinks have been fixed, but there are tweaks still being made. Keep in mind that by modifying your device it could damage it and you do so at your own risk. For the XDA post with all the files and instructions, click the second source link.
Source: XDA Developers, XDA Forums