[tomoco]

Esto es lo que pone en xda sobre desbloquear el bootloader con el teléfono liberado

 Cita:

You do not need to have a sim lock on your phone to unlock your bootloader.

Recommended: Disable your antivirus (it might find a "virus" in ADB.exe even though there isn't one and might even interfere in bootloader unlocking process) Use stock rom (I managed to unlock bootloader on GingerDX v013 though and users have managed to unlock it in Froyobread v23b and MiniCM7 2.0.7)

Note: Unlocking the bootloader of your phone will restore the original sim lock of your phone (if you had any) unless if you unlocked with EMMA/IMEI unlock code or it was factory-unlocked or if SE unlocked it!

However, some users have reported that using msm7227_semc.cmd on their sim-unlocked phones did not restore the sim lock onto their phone. This has not been confirmed as of yet. Unlock the bootloader on your sim unlocked phone AT YOUR OWN RISK!

Según entiendo yo si que se puede desbloquear el bootloader con el teléfono liberado. El único inconveniente es que recuperas el sim-lock y por lo tanto dejar de ser libre, al menos que lo liberases por IMEI, EMMA o ya sea libre de origen. En estos tres casos el teléfono seguiría liberado después de desbloquear el bootloader.