Preparing for deployment

It is generally not recommended to hard-code physical on-NAND locations in case of factory bad blocks or block failures in the field. [1] Instead it is preferable to set up partitions on the chip with a generous safety margin and to store data in a location-independent way. This is commonly achieved by placing logical tags in the spare area of each page, or using a log-structured filesystem such as YAFFS. Such strategies remove the dependence on physical addressing, at the cost of increased complexity.

The upshot of this is that you cannot reliably create a simple binary image to bulk-program in the factory. A more complicated programming operation is required to take account of your chip partitions, logical addressing strategy and any bad blocks which may be encountered during write.



Usually the first block is guaranteed to be defect free for a certain number of erase cycles. This tends to be necessary if bootstrapping the CPU off NAND, and is an obvious exception to this rule.

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