Method of error correction in a flash memory

A method of error correction in a nonvolatile flash memory of NAND type, said flash memory comprising a set of blocks which the application accesses in read mode or in write mode or in erase mode, each block comprising a plurality of pages, said memory comprising a first and a second, identical, copies of software to be loaded, the first and the second copies of the software physically occupying an equal number of distinct blocks, a page of a block occupied by data of the first copy of the software being corrupted, and a page of a block occupied by data of the second copy of the software being corrupted, said method comprising the execution of a boot loading program implementing the following steps:

• an attempted loading of the first copy of the software by the boot loading program;
• discovering by the boot loading program that at least one page of a block occupied by the first copy of the software is corrupted;
• recording of an identification of said at least one corrupted page in a persistent memory of the flash memory;
• configuring the boot loading program so that it loads the second copy of the software at the next execution;
• re-executing of the boot loading program;
• an attempted loading of the second copy of the software by the boot loading program;
• discovering by the boot loading program that at least one page of a block occupied by the second copy of the software is corrupted;
• recording of an identification of said at least one corrupted page in a persistent memory of the flash memory;
• the replacement of the block occupied by the second copy of the software comprising a corrupted page with the identical block occupied by the first copy of the software not comprising any corrupted page, making it possible to correct the second copy of the software;
• re-executing of the boot loading program;
• and
• the loading of the second copy of the software.