how do I relock bootloader? topic

I got an update on my Xperia M2(d2305) to 4.4.4. I rooted my phone when it was 4.4.2. When I try to update it, it shows an error where it says (Sony update engine failure error 2003). I unroot my phones using the factory data reset but still with the same error. When I checked the bootloader it still say YES. .how do i lock back?

[Q] ReLock Moto G 4g UK topic

I've unlocked my Moto G $g. I want to undo my actions and return the device to its original state: unrooted and locked. What is the easiest way to do this?

[Q] HELP for relock bootloader on Sony XPERIA T LT30p topic

HI I want to ask something? I have unlocked bootloader and I spent new Rom. if the relock the bootloader lost the Rom who have passed? how to become mem miss the new Rom have spent on mobile???