1Allwinner NAND flashing 2======================= 3 4A lot of Allwinner devices, especially the older ones (pre-H3 era), 5comes with a NAND. NANDs storages are a pretty weak choice when it 6comes to the reliability, and it comes with a number of flaws like 7read and write disturbs, data retention issues, bloks becoming 8unusable, etc. 9 10In order to mitigate that, various strategies have been found to be 11able to recover from those issues like ECC, hardware randomization, 12and of course, redundancy for the critical parts. 13 14This is obviously something that we will take into account when 15creating our images. However, the BROM will use a quite weird pattern 16when accessing the NAND, and will access only at most 4kB per page, 17which means that we also have to split that binary accross several 18pages. 19 20In order to accomodate that, we create a tool that will generate an 21SPL image that is ready to be programmed directly embedding the ECCs, 22randomized, and with the necessary bits needed to reduce the number of 23bitflips. The U-Boot build system, when configured for the NAND will 24also generate the image sunxi-spl-with-ecc.bin that will have been 25generated by that tool. 26 27In order to flash your U-Boot image onto a board, assuming that the 28board is in FEL mode, you'll need the sunxi-tools that you can find at 29this repository: https://github.com/linux-sunxi/sunxi-tools 30 31Then, you'll need to first load an SPL to initialise the RAM: 32sunxi-fel spl spl/sunxi-spl.bin 33 34Load the binaries we'll flash into RAM: 35sunxi-fel write 0x4a000000 u-boot-dtb.bin 36sunxi-fel write 0x43000000 spl/sunxi-spl-with-ecc.bin 37 38And execute U-Boot 39sunxi-fel exe 0x4a000000 40 41On your board, you'll now have all the needed binaries into RAM, so 42you only need to erase the NAND... 43 44nand erase.chip 45 46Then write the SPL and its backup: 47 48nand write.raw.noverify 0x43000000 0 40 49nand write.raw.noverify 0x43000000 0x400000 40 50 51And finally write the U-Boot binary: 52nand write 0x4a000000 0x800000 0xc0000 53 54You can now reboot and enjoy your NAND.