I'm trying to unlock boot loader on my Xperia S.
I tried the official way - via Sony Development site but I get stuck on the step where you have to connect the phone and push Volume Up button. Problem is that the phone enters the fastboot mode for 5 seconds, but then shows the battery charging logo and it 'quits' the fastboot mode.
Also, when the phone enters the fastboot mode, I should be asked for a driver, but I'm not.
Later I tried using the fastboot tool, found here, but the instructions aren't clear, because it seems that the new version is slightly different as the older one. Anyways, when I want to fastboot it (labeled with B) it enters the fastboot mode for 5 seconds, then the phone turns on again.