It's ok now! I had to edit the kernel (adding force_erase flag) and there is also a similiar check in flash_eraseall tool ;) Stanislav -------- Original Message -------- Hi, I read fome of your answers in linux forums (http://osdir.com/ml/linux.file-systems.yaffs/2007-04/msg00002.html) I have the same issue but I need to clear the bad block markers in NAND. I don't have nand_scrub in my u-boot so I need to do that it kernel. What should I change and implement in the driver so it will format (erase) the oob? Thanks in advance, Stanislav