Method of assembling or disassembling a rotor blade of a wind turbine

A method (800,900) of assembling or disassembling a rotor blade of a wind turbine, the wind turbine comprising a tower, a nacelle mounted on the tower and a rotor coupled to the nacelle, the rotor having a rotor hub and a rotor blade, the rotor blade comprising a first blade segment connected with the rotor hub, a second blade segment, wherein the second blade segment is configured for joining to the first blade segment such that the second blade segment extends from the first blade segment towards a blade tip of the rotor blade, and a releasable locking device configured for joining the second blade segment to the first blade segment, the releasable locking device comprising a structural member of the second blade segment, the structural member being configured for engaging a further structural member of the first blade segment for releasable locking with the further structural member, wherein a fastening device of the second blade segment is arranged on the structural member; the method comprising raising (950) or lowering (860) the second blade segment using a connecting device fastened to the fastening device of the second blade segment, wherein the connecting device extends through a root of the rotor blade and at least partially through the first blade segment to the second blade segment.