Sony Ericsson Xperia X10 : Downgrade X10i From 2.1 To 1.6

Some people keep asking how to downgrade back to 1.6. So I wanted to provide how to do it

Note: This will give you UK Generic R1FA016 firmware

1) Install SEUS (Sony Ericsson Update Service).
You can get it from here: http://www.sonyericsson.com/cws/down...-2.10.6.21.exe

2) Run SEUS, follow the prompts. You don't need to update the phone through it, but get the phone ready for updating. This process should install the drivers necessary for the rooting process.

Note: I suggest you keep your USB cable attached to that USB port. Remember which USB port of your computer it's attached to, as changing USB ports can lead to a bit of confusion for the next 2 steps!

3) To check if #2 was successful, click on Start, click Run, and type: regedit
In the Registry Editor that pops up, click on Computer, press CTRL+F, and search for this: USBVid_0fce&Pid_adde

After it's finished finding, on the right side you'll see DeviceInstance, then it says REG_SZ, then it says something like USBVid_0fce&Pid_adde5&270d2a78&0&3 You'll need that last bit (in this example: 5&270d2a78&0&3 Yours would probably be different). This is your DeviceID (you'll need it soon!)

Note: You may have multiple of these if you plugged the USB cord into many USB ports on your computer. Each USB port will give a different DeviceID, so if you have more than one DeviceID, you'll have to choose one, and if it doesn't work (you'll find out when you reach #5!) you will have to choose another one.

Alternatively, download the file in the next step and extract it, go to the folder called 1st, and run the DeviceID.jar file. It should give your DeviceID

4) Download this:
Download R1FA16 rar
or from here: [url]
Extract it.
In the step1 folder, you'll see a file called DeviceID.txt Open it up, delete whatever's there, and put YOUR DeviceID (that you found from the previous step). Save the file and close notepad.

Note: Make sure there are no extra spaces or lines after/before the DeviceID. The ONLY thing that should be in the file is your DeviceID, NO SPACES/LINES (for example, only this: 5&270d2a78&0&3 [yours will probably be different])

5) Take out the USB cable from your phone (leave it plugged into your computer) Turn your phone OFF. Open up step1.cmd (it's not inside the step1 folder, but outside it), but DON'T PRESS ANYTHING

Now we have to put the phone into flash mode. This is how you do it:
Hold the Back button on your phone, and while holding the back button, insert the USB cable into the phone. A green light should come on the phone (like when it's charging or a missed call) Quickly "Press any key to continue..." in the open step1.cmd window.

Let it finish what it's doing. It will say "Press any key to continue..." after it's finished. Until then, DON'T touch anything!

If you get problems in this step, refer to this post:[url]

Here's a helpful video for common java issue: [ROOT/De-Brick Guide] Java Issue 64 bit Fix Walkthrough (Video guide included) - xda-developers

After completion, this will give you a Generic X10i R1FA016 firmware (check it by pressing the left button, go to settings>about phone and at the very bottom under build number)
Keep your phone plugged into the USB.

6) Run SEUS to get to the latest firmware (do this before 2.1 is released in the UK if you don't want 2.1)