The new bootloader is not actually locked, it's changed to use QPST (Qualcomm Product & Support Tools). As it needs a code, we can't use it.
This method flashes the B518 bootloader straight to your phone, so you will get back USB.
Apply only if you have upgraded your phone to B522 or newer. You may have a custom ROM on top, but the base has to be B522 or newer.
Tested by myself on B522, B526 & B528.
The steps required to get back pink/blue screen USB:
Automatic flashable zip is pretty much fail proof, but I have warned you.
Automatic method (recommended):
- Download update-B518-bootloader.zip from MediaFire.
- Save it to the root of your SD Card.
- Start the phone in recovery mode (recommended recovery is 188.8.131.52)
- Select "install zip from sdcard"
- Select "chooze zip from sdcard"
- Select the zip you downloaded before.
- Select yes.
- Reboot and enjoy!
Manual method (not recommended):
- Download the bootloader.bin (B518) from MediaFire.
- Copy it to the root of your SD card.
- Use a Terminal Emulator if on phone or start ADB and write in "adb shell".
- Write in "su" to get root rights.
- Write in "dd if=/sdcard/bootloader.bin of=/dev/block/mmcblk0p3" to copy the bootloader.bin from SD card to the bootloader partition.
- All done!
Protip: When using Linux distribution, pink screen mounts your internal SD card, data, cache and system partitions. This happens because Windows does not mount extX partitions by default.
I suggest everyone to do this as long as you have rooted your phone and want to flash custom ROMs/kernels.
Now you can recreate your backups with this tutorial.
Special thanks to dancer_69, who sent me B518 bootloader.