A system, comprising: a first resistive nonvolatile memory array; a second transistor-based nonvolatile memory array; and a memory controller configured to: read data bits stored in the first resistive nonvolatile memory array; write the data bits read from the first resistive nonvolatile memory array and an indicator bit to the second transistor-based nonvolatile memory array, the indicator bit indicating whether data bits stored in the second transistor-based nonvolatile memory array are valid; determine whether the indicator bit is valid in response to a power up of the system after a high-temperature event, a received command after a high-temperature event, a predetermined number of power ups, or a power up or received command after each of a predetermined number of high-temperature events; and write the data bits stored in the second transistor-based nonvolatile memory array to the first resistive nonvolatile memory array when the indicator bit is valid; wherein the first resistive nonvolatile memory array is further configured to store look-ahead bits, and the look-ahead bits serve as indicators of data corruption or systematic drift of the first resistive nonvolatile memory array and a total number of the look-ahead bits is less than a total number of the data bits; and wherein the memory controller is further configured to. determine a number of defective bits among the look-ahead bits in response to a power up of the system after a high-temperature event, a received command after a high-temperature event, a predetermined number of power ups, or a predetermined number of received commands; compare the number of defective look-ahead bits to a threshold number of defective look-ahead bits; and write the data bits stored in the second transistor-based nonvolatile memory array to the first resistive nonvolatile memory array when the number of defective look-ahead bits equals or exceeds the threshold number of defective look-ahead bits. a first resistive nonvolatile memory array; a second transistor-based nonvolatile memory array; and a memory controller configured to: read data bits stored in the first resistive nonvolatile memory array; write the data bits read from the first resistive nonvolatile memory array and an indicator bit to the second transistor-based nonvolatile memory array, the indicator bit indicating whether data bits stored in the second transistor-based nonvolatile memory array are valid; determine whether the indicator bit is valid in response to a power up of the system after a high-temperature event, a received command after a high-temperature event, a predetermined number of power ups, or a power up or received command after each of a predetermined number of high-temperature events; and write the data bits stored in the second transistor-based nonvolatile memory array to the first resistive nonvolatile memory array when the indicator bit is valid; read data bits stored in the first resistive nonvolatile memory array; write the data bits read from the first resistive nonvolatile memory array and an indicator bit to the second transistor-based nonvolatile memory array, the indicator bit indicating whether data bits stored in the second transistor-based nonvolatile memory array are valid; determine whether the indicator bit is valid in response to a power up of the system after a high-temperature event, a received command after a high-temperature event, a predetermined number of power ups, or a power up or received command after each of a predetermined number of high-temperature events; and write the data bits stored in the second transistor-based nonvolatile memory array to the first resistive nonvolatile memory array when the indicator bit is valid; wherein the first resistive nonvolatile memory array is further configured to store look-ahead bits, and the look-ahead bits serve as indicators of data corruption or systematic drift of the first resistive nonvolatile memory array and a total number of the look-ahead bits is less than a total number of the data bits; and wherein the memory controller is further configured to. determine a number of defective bits among the look-ahead bits in response to a power up of the system after a high-temperature event, a received command after a high-temperature event, a predetermined number of power ups, or a predetermined number of received commands; compare the number of defective look-ahead bits to a threshold number of defective look-ahead bits; and write the data bits stored in the second transistor-based nonvolatile memory array to the first resistive nonvolatile memory array when the number of defective look-ahead bits equals or exceeds the threshold number of defective look-ahead bits. determine a number of defective bits among the look-ahead bits in response to a power up of the system after a high-temperature event, a received command after a high-temperature event, a predetermined number of power ups, or a predetermined number of received commands; compare the number of defective look-ahead bits to a threshold number of defective look-ahead bits; and write the data bits stored in the second transistor-based nonvolatile memory array to the first resistive nonvolatile memory array when the number of defective look-ahead bits equals or exceeds the threshold number of defective look-ahead bits.