1. Download and place the RecoverX tool archive onto your Desktop.
2. Unzip files from the archive to your Desktop.
3. Turn ON the USB debugging function on your device by heading to Menu>>Settings>>Applications>>Development>>USB debugging.
4. Once enabled, connect your device to your PC via USB cable.
5. Double-click on the RecoverX executable file you have on your Desktop and it’ll launch.
6. Select Sony Ericsson from the Brand dropdown menu.
7. Select Xperia X10 from the Device dropdown menu as shown below:

Select Brand and your Device
8. Hit Next button given in the bottom-right corner.
9. Follow the on-screen instructions.
10. And you’re all set!
Awesome! Your device has been successfully equipped with a custom recovery and from now onward, you can enjoy flashing custom ROMs, Tweaks, Mods and so on.