Before you start you will need to check if your bootloader is unlockable. To do this, open your phonepad/dialer and type *#*#7378423#*#*. Tap service info and then configuration. Look to rooting status, there you will find a string of text what reads "Bootloader unlock allowed:" if it says yes then you can unlock your bootloader (and I will help you to unlock it as much as I can), however if it says no there is no way to unlock it.
My Phone: Sony Xperia Z1 Compact | ROM: Modified Stock | Base Firmware/BuildNumber: 14.4.A.0.108 | Android Version: 4.4.4 | Kernel: Stock (Unlockable Bootloader) | Network: giffgaff Stolen
My Tablet: Google Nexus 7 (2012) | ROM: CM11 | Base Firmware/Build Number: 11-20140527-NIGHTLY-grouper | Android Version: 4.4.4 | Kernel: CM11 | Network: N/A
Backup/Development Phone: Sony Xperia M C1905