In this paper, we propose a Blockchain-based solution for the recovery of an SDN controller back to a previously known state upon sudden failure. A lightweight minimal Blockchain ledger containing metadata details about each controller event is maintained by the switches. The set of all instructions given by the controller to the switches denotes the state of the controller at that instant. Whenever a new event occurs, the meta-information about it gets stored in the Blockchain which is updated in the switches after regular epochs. Upon sudden failure and subsequently coming back online again, the controller downloads all the tables and information from the respective switches. It checks and compares the metadata contained in the Blockchain with those data received from the switches. In addition to the existing security services provided by Blockchain, the proposed scheme can further solve the controller failure problem. The performance of the proposed solution is measured through simulation. The proposed scheme with the metadata-based solution saves about 75% of space and a controller can securely recover with a duration of 50 Sec.