Inoperable bits are determined in a memory block. Rather than abandon the block as inoperable, a data structure is generated that includes at least one memory page pointer that identifies the location of the inoperable bits in the memory block. The data structure is stored in one of a group of memory blocks that are reserved for the data structures. A pointer to the data structure is stored in metadata associated with the memory block with the inoperable bits. When a later memory operation is received for the memory block, the pointer is retrieved from the metadata and the memory page pointers are used to avoid the inoperable bits.