A method includes, in a non-volatile memory that includes multiple memory blocks, defining a redundancy zone that includes at least an old parity block, a new parity block and multiple active blocks of which one block is defined as an open block. Data is stored in the redundancy zone and the stored data is protected, such that new input data is stored in the open block, redundancy information for the active blocks including the open block is stored in the new parity block, and the redundancy information for the active blocks excluding the open block is stored in the old parity block. Upon filling the open block and the new parity block, an alternative block is assigned to serve as the open block and the new parity block is assigned to serve as the old parity block.