Hi , Scott:

First, My uboot version is 2013.04.

In the function scan_write_bbt(), U-boot uses MTD_OOB_PLACE to write BBT data and BBT pattern. See ">>>" below

static int scan_write_bbt(struct mtd_info *mtd, loff_t offs, size_t len,

uint8_t *buf, uint8_t *oob)

{

struct mtd_oob_ops ops;

...

...

ops.mode = MTD_OOB_PLACE;

ops.ooboffs = 0;

ops.ooblen = mtd->oobsize;

ops.datbuf = buf;

ops.oobbuf = oob;

ops.len = len;

return mtd->write_oob(mtd, offs, &ops);

}

while in funtion search_bbt() (actually in function scan_read_raw_oob()), U-boot uses MTD_OOB_RAW to read BBT data and BBT pattern. See ">>>" below.

static int scan_read_raw_oob(struct mtd_info *mtd, uint8_t *buf, loff_t offs,

size_t len)

{

struct mtd_oob_ops ops;

int res;

...

...

ops.mode = MTD_OOB_RAW;

ops.ooboffs = 0;

ops.ooblen = mtd->oobsize;

while (len > 0) {

if (len <= mtd->writesize) {

ops.oobbuf = buf + len;

ops.datbuf = buf;

ops.len = len;

return mtd->read_oob(mtd, offs, &ops);

} else {

ops.oobbuf = buf + mtd->writesize;

ops.datbuf = buf;

ops.len = mtd->writesize;

res = mtd->read_oob(mtd, offs, &ops);

if (res)

return res;

}

buf += mtd->oobsize + mtd->writesize;

len -= mtd->writesize;

}

return 0;

}

It's confused that search BBT and write BBT uses different mtd ops mode. And also data will not be valid if U-boot uses mtd ops MTD_OOB_RAW during reading and no software ECC is implemented.

I also noticed that in U-boot2013.07 both search BBT and write BBT uses mtd ops MTD_OPS_PLACE_OOB.

Best wishes,