There is no certain time frame provided by Sony Ericsson since their Xperia devices were running 1.6 for firmware update. Rumors were that Xperia x10 was supposed to get the official update by October this year. Anyhow, a senior member at XDA has developed a flash tool for Xperia x10 (x10, x10a, x10i). Users have reported a positive feedback since the utility can flash and install Android 2.1 Eclair on Xperia.
Before we get any further in the process, make sure to back up your phone and wipe all user data. (wipe is necessary). Lets look at this guide to upgrade your Xperia device to 2.1 Eclair.
1. Download these files on your desktop:
2. Extract Xperia X10 Firmware and x10Flash-2.1 file
3. Connect your Xperia device to the computer
4. Copy the extracted ‘X10 Firmware’ to Firmware sub-directory in x10Flash-2.1 folder
5. Execute x10Flash.bat
6. Wait for the process to finish
7. Hit enter when you get the notification prompt
8. Unplug x10 and wait till it gets booted
(if it doesn’t boot automatically, press POWER button)
9. It will take 3 to 5 minutes to complete the process.
And you have successfully installed 2.1 Eclair on your X10 device.