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==Introduction==
With respect to the NOR flash memories, NAND devices are known to be quite challenging with regard to the reliability. This is especially true when the NAND flash is used as the boot device. Several techniques such as wear leveling and bad block management have to be implemented to achieve an acceptable reliability.
==Test bed==
The test bed used in this example consists of an i.MX6SoloX-board equipped with a 512MB 8-bit asynchronous 1-bit ECC SLC NAND memory which is connected to the EIM bus of the SoC. The boot firmware image is the U-Boot bootloaderbinary file (<code>mx6sx_board_nand_u-boot.imx</code>). Its size is about 400 kB. From the point of view of MTD partitions, the boot partition is <code>mtd0</code> which is 8MB.
==Boot partition organization==
mtd: We write one page for save guard. *
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In this case, the boot partition–<code>/dev/mtd0</code>, indicated as a parameter of the command line–is 8MB. For this reason, the secondary firmware image is stored at the address 0x480000, that is at the half of the available space after the first MB ( (0x800000-0x100000)/2 ).
