1*4882a593SmuzhiyunAllwinner NAND flashing 2*4882a593Smuzhiyun======================= 3*4882a593Smuzhiyun 4*4882a593SmuzhiyunA lot of Allwinner devices, especially the older ones (pre-H3 era), 5*4882a593Smuzhiyuncomes with a NAND. NANDs storages are a pretty weak choice when it 6*4882a593Smuzhiyuncomes to the reliability, and it comes with a number of flaws like 7*4882a593Smuzhiyunread and write disturbs, data retention issues, bloks becoming 8*4882a593Smuzhiyununusable, etc. 9*4882a593Smuzhiyun 10*4882a593SmuzhiyunIn order to mitigate that, various strategies have been found to be 11*4882a593Smuzhiyunable to recover from those issues like ECC, hardware randomization, 12*4882a593Smuzhiyunand of course, redundancy for the critical parts. 13*4882a593Smuzhiyun 14*4882a593SmuzhiyunThis is obviously something that we will take into account when 15*4882a593Smuzhiyuncreating our images. However, the BROM will use a quite weird pattern 16*4882a593Smuzhiyunwhen accessing the NAND, and will access only at most 4kB per page, 17*4882a593Smuzhiyunwhich means that we also have to split that binary accross several 18*4882a593Smuzhiyunpages. 19*4882a593Smuzhiyun 20*4882a593SmuzhiyunIn order to accomodate that, we create a tool that will generate an 21*4882a593SmuzhiyunSPL image that is ready to be programmed directly embedding the ECCs, 22*4882a593Smuzhiyunrandomized, and with the necessary bits needed to reduce the number of 23*4882a593Smuzhiyunbitflips. The U-Boot build system, when configured for the NAND will 24*4882a593Smuzhiyunalso generate the image sunxi-spl-with-ecc.bin that will have been 25*4882a593Smuzhiyungenerated by that tool. 26*4882a593Smuzhiyun 27*4882a593SmuzhiyunIn order to flash your U-Boot image onto a board, assuming that the 28*4882a593Smuzhiyunboard is in FEL mode, you'll need the sunxi-tools that you can find at 29*4882a593Smuzhiyunthis repository: https://github.com/linux-sunxi/sunxi-tools 30*4882a593Smuzhiyun 31*4882a593SmuzhiyunThen, you'll need to first load an SPL to initialise the RAM: 32*4882a593Smuzhiyunsunxi-fel spl spl/sunxi-spl.bin 33*4882a593Smuzhiyun 34*4882a593SmuzhiyunLoad the binaries we'll flash into RAM: 35*4882a593Smuzhiyunsunxi-fel write 0x4a000000 u-boot-dtb.bin 36*4882a593Smuzhiyunsunxi-fel write 0x43000000 spl/sunxi-spl-with-ecc.bin 37*4882a593Smuzhiyun 38*4882a593SmuzhiyunAnd execute U-Boot 39*4882a593Smuzhiyunsunxi-fel exe 0x4a000000 40*4882a593Smuzhiyun 41*4882a593SmuzhiyunOn your board, you'll now have all the needed binaries into RAM, so 42*4882a593Smuzhiyunyou only need to erase the NAND... 43*4882a593Smuzhiyun 44*4882a593Smuzhiyunnand erase.chip 45*4882a593Smuzhiyun 46*4882a593SmuzhiyunThen write the SPL and its backup: 47*4882a593Smuzhiyun 48*4882a593Smuzhiyunnand write.raw.noverify 0x43000000 0 40 49*4882a593Smuzhiyunnand write.raw.noverify 0x43000000 0x400000 40 50*4882a593Smuzhiyun 51*4882a593SmuzhiyunAnd finally write the U-Boot binary: 52*4882a593Smuzhiyunnand write 0x4a000000 0x800000 0xc0000 53*4882a593Smuzhiyun 54*4882a593SmuzhiyunYou can now reboot and enjoy your NAND.