However, this minor update has reportedly improved performance, especially in Timescape and Mediascape. The update is R1FB001 and baseband version 1.0.21. For now, the update is only available for phones running the Nordic and American firmware.
For the rest of the world it is not available yet. I tried in India and found no new updates. I will give an update on this within sometime. It is good to see Sony Ericsson taking seriously their Xperia X10 users.