Yaffers, Thanks very much for all the help. On my 2.4 kernel my yaffs_oobinfo looks like: $7 = {useecc = 1, eccbytes = 6, oobfree = {{0, 0}, {0, 0}, {0, 0}, {0, 0}, {0, 0}, {0, 0}, {0, 0}, {0, 0}}, eccpos = {8, 9, 10, 13, 14, 15, 0 }} and mtd->oobavail=8 an example oob looks like: 00004c40: 0300 1037 ffff 0601 5566 5b68 c1ff ffff ...7....Uf[h.... I'm guessing the format is: T0,T1,T2,T3,P,B,T4,T5,E0,E1,E2,T6,T7,E3,E4,E5 On yaffs2, for backward compatibility with the above, should I set nand_oob_16 to -------------------------------------------- static struct nand_ecclayout nand_oob_16 = { /* use older yaffs1 layout */ .eccbytes = 6, .eccpos = { 8, 9, 10, 13, 14, 15 }, .oobavail = 9, .oobfree = { { 0, 4 }, { 6, 2 }, { 11, 2 }, { 4, 1 } }}; -------------------------------------------- with CONFIG_YAFFS_9BYTE_TAGS=y or -------------------------------------------- static struct nand_ecclayout nand_oob_16 = { /* use older yaffs1 layout */ .eccbytes = 6, .eccpos = { 8, 9, 10, 13, 14, 15 }, .oobavail = 8, .oobfree = { { 0, 4 }, { 6, 2 }, { 11, 2 } }}; -------------------------------------------- with CONFIG_YAFFS_9BYTE_TAGS not set? One other question, what does the line in Kconfig refer to: -------------------------- older-style format. See notes on tags formats and MTD versions. -------------------------- Is there something written up on "tags formats and MTD versions"? I'd love to read all about it if there is... Thanks again for all of the help. Rick