This method can be applied on almost all the Sony Xperia devices (not only on the Android based smartphones), so you have nothing to worry about; furthermore the present tutorial will show you which is the official and universal operation that can be used for unlocking the bootloader of your Sony branded gadget, all the info needed being explained and detailed during the lines from below. (android.gs)
Simply select Unlock - Method 1 in left hand corner and click on Unlock Bootloader button below. (phonehorn.com)
HTC Android mobile phones from will come with unlocked bootloaders as the company has today dissolved its locked bootloader policy for Android mobile phones. (gadgetian.com)