It works like a charm on X10a
HSPDA network works. (i.e.: 3G in my region)
Here's what happens:
You download the two files listed by Binary
Put the extracted firmware in the firmware directory (along with loader.sin)(10 sin files together)
Open the .bat file (type in 1, 2 , 3 or 4 depending on your windows version).
It will ask you: Please plug Xperia in flash mode so,
Turn off your phone, press back and plug the usb cable! and Hit enter ( you should be quick, if you take to long it may not work, you have about 5 seconds. You know you are in flash mode because de GREEN LED on your X10 will stay ON)
Your device will stay with the screen off while flashing. The .bat will be running and running like mad for about 2-3 minutes. After that WAIT for windows to tell you that it has finished. Hit ENTER. The .bat WILL CLOSE.
On your device: Unplug your USB cable, wait for it to boot. I waited for like 2 minutes and nothing so I had to press POWER again.
A device and a camera with a BLUE arrow will appear on your device screen. WAIT, WAIT, WAIT. It will reboot, and take like 2 minutes on sony ericson screen.
It will boot up eventualy.
Now lets go root! : http://forum.xda-developers.com/showthread.php?t=824788
Just download the SuperOneClickv1.5.1-ShortFuse version. I didn't use any other of those files attached in the link above.
Turn USB debugging on. Settings -> Aplication -> Development
Conect on USB (it should show on notification that you are debugging.)
Press root. (on windows)
It doesn't work, it stays in "Running rageagainstthecage..."
You should now tick/untick the USB debugging mode on your phone to make it work. (just look at the oneclick terminal. If it is halted untick/tick, wait till it stops again.
Took me like 5 minutes, and ROOTED appeared on my laptop screen.
BARNACLE WIFI TETHER WORKS
Binary, somebloke, CVCHETAN, XperiaX10iUser, developers on supleroneclickroot, imugur and Reb0rn for making it all possible!
(we now have Rooted Android 2.1
something that was possible since the beggining of the year on mhy G1 LOL.)