Re lock Sony Xperia P LT22i phone bootloader now possible. If you have a similar variant with a different region code such as LT22a this method work. But its better flash international firmware before apply this method. However this method works only with the device which used official unlocking method. If you use test point or any-other method, this method doesn’t work for you.
We need to relock and unroot the phone before we submit it to the service center, otherwise they will reject the warranty. After you follow this guide and flash official Sony firmware, you can again claim the warranty.
- Enable usb debugging ( Settings > Developer options ).
- Fully charge device.
- Stock Sony firmware.
- Flashtool latest version in here.
- Bootloader relock file xperia P.
- Xperia P latest firmware 6.1.1.B.1.54
- Copy downloaded firmware and relock file into the flashtool installed location firmware folder ( C:\Flashtool\firmwares).
- Run flashtool as administrator.
- Power off the phone and wait for a few seconds, now press and hold the volume down key and same time connect the phone to the computer and release the volume down key.
- Click flashtool “thunder” symbol, and mode selector window tick “mode selector” and firmware select your relock file and click “OK”.
- Wait for a few seconds to complete the installation.
- After it’s complete using above same process flash downloaded stock firmware, or you can install the latest firmware using the Sony update service. Or just flash this 6.1.1.b.1.54 kernel.
- When the installation has completed, disconnect the phone from the computer and power on.
Phone fully booted dial *#*#7378423#*#* in your keypad.
- Go to the “Service > Configuration” and under the “Root status” check if there’s “Bootloader unlock allow : Yes”. If there’s exact same, you have locked bootloader.