Xperia X10 Stuck on 'Sony Ericsson' logo (boot screen)

If your Sony Ericsson Xperia X10 won't go past the Sony Ericsson boot logo due to some unfortunate sequence of updates that you performed, your best bet is to use the flasher utility and flash Android 2.3 (The Kernel and the file system).

You may encounter any of these two scenarios:

1. The power button is working and you can turn on/off the phone using it.
2. The power button is dead and you have to pull out the battery to power off the phone. Putting the battery back in reboots the phone automatically with the phone getting stuck at the Sony Errison logo.

Here is the solution:

1. Download the Android 2.3 flasher here. (Size: 220MB. I have uploaded the file on Mediafire.)
2. Extract the file and execute "X10FlashTool.exe" 
   
   
3. Click on the "Flash" button.
   
   
4. Choose the "x10 2.3 aro" firmware, check "Wipe User Data" and click the "OK" button.
   
   
5. The flasher will ask you to connect your phone to the PC while pressing the back button.
   
   • Scenario 1: Your phone is switched off - Easy. Just connect the phone as expected.
   • Scenario 2: Your phone automatically displays the Sony Ericsson logo when you put the battery in. Do this:
     1. Pull out the battery
     2. Connect the USB cable.
     3. Put the battery back in while pressing the back button. That should do the trick.
   
   Tip: It is easier to connect the USB cable at the phone's end rather than at the PC end.
6. Wait for while for the flasher to do it's job. It takes a while to flash the kernel and the FS. The flasher will ask you to disconnect your phone when it's done.
   
   
7. Chances are that you won't be able to power off the phone, in which case remove the battery, wait for at least 5 seconds and then put it back in. Try turning on the phone. If the phone doesn't turn on, connect the USB cable and try turning on the phone again. It should boot now.
8. Wait for a while (it takes longer as this is the first boot). For me it took about 2 minutes to get past the Sony Ericsson logo and display the Sony animation.

For those interested in history:

Recently I was trying to update my Xperia X10 to Android 4.1 Jelly bean and guess what, I ended up bricking it twice. The phone would boot up, but just displayed the Sony Erisson logo. This happened twice while updating:

1. The first time, the power button was working and I could turn on/off my phone using it.
2.  The second time, the power button was dead and I had to pull out the battery to power off the phone. Putting the battery back in rebooted the phone automatically with the phone getting stuck at the logo.

I waited and waited and realized that I had screwed it up. That is when I searched the internet on what to do, but nothing really worked.

The good news:
I could see that my device was recognized by the device manager on the PC as a Sony Erisson device. Well there was the silver lining!

Well I tried using the Sony Erisson update service, which obviously didn't work.
My next plan was to use the Android 2.3 flasher utility which I already had and used about a year ago. Of course I ran out of other options...lol
Imagine my astonishment when It worked.

Hope this does the trick for someone who has just lost hope ;-)
Now I can perform some crazy updates on my X10 without fear :-)