Method of identifying and preparing a key block in a flash memory system and memory controller therefor

A memory controller, comprising:

• a first port configured to couple to a memory array;
• the memory controller configured to:
• select a candidate key block in the memory array, the memory array including a second memory block operating in a normal mode;
• check a quality of the candidate key block using a non-data wordline of the candidate key block;
• associate a first set of parameters with the candidate key block, the first set of parameters including a first erase parameter, a first program parameter and a first read parameter;
• register the candidate key block as a key block,
• receive a value indicative of temperature of the memory array;
• determine the value indicative of temperature is above a temperature threshold amount;
• in response to determining the value indicative of temperature is above the temperature threshold amount, performing a read scrub operation on the key block to retrieve key data in the key block as second key data,
• determine a bit error rate of the second key data is above a bit error rate threshold amount;
• and
• in response to determining the bit error rate of the second key data is above the bit error rate threshold amount, moving the second key data to a second key block.

A non-volatile storage system, configured to monitor a key block, comprising:

• a memory array storing a first data in a first block of memory in the memory array, wherein the first block is accessed using a first set of parameters and the first block is a key block;
• and
• a controller coupled to the memory array, wherein the controller is configured to:
• determine a check event has occurred associated with the key block, wherein the check event comprises a temperature of the storage system rising above a temperature threshold amount;
• in response to determining the check event has occurred, perform a read scrub on the key block to retrieve the first data as second data;
• determine a bit error rate of the second data is above a bit error rate threshold amount;
• and
• in response to determining the bit error rate of the second data is above the bit error rate threshold amount, move the second data to a second key block in the memory array.