US Patent 8446787 Replacing defective memory blocks in response to external addresses

Electronic systems and methods of operating memory devices are provided. In one such embodiment, a memory device receives an external address that addresses a non-defective memory block of a sequence of memory blocks of the memory device in place of a defective memory block of the sequence of memory blocks such that the non-defective memory block replaces the defective memory block. The non-defective memory block is proximate non-defective memory block following the defective memory block in the sequence of memory blocks that is available to replace the defective memory block.