The present disclosure generally relates to methods and systems for allocating free blocks as decommissioned blocks to replace bad blocks. In certain embodiments, when there are insufficient free blocks in a free block list to replace a bad or defective block for a CE, an FTL scans blocks stored in an unallocated block repository. If there are unallocated blocks available for the CE, one or more is reallocated as free blocks and used to replace the bad or defective block. When only one or no further unallocated blocks for the CE are available, the FTL places the CE in a read-only mode.