Flashing firmwares can sometimes be a bit fiddly and following instructions on rooting, recovery, clearing your cache etc can become a bit overwhelming.

Now to help you perform these functions is FlashTool for your XperiaX10 by XDA forum members Bin4ry and Androxyde.

FlashTool is an all in one tool that can flash original images (Android 1.6 and 2.1 images), root, install and recover, clean your ROM and clear your cache.

Before you can flash, you need to connect your device in Flashmode. Note that you should wipe userdata if you switch between Android version (1.6 <-> 2.1). If you do not do this, your phone will keep restarting all the time.

For more information including available firmwares for FlashTool, and to download the tool, head on over to the application thread.