Printable Version of Topic

Click here to view this topic in its original format

OESF Portables Forum _ Zaurus - Hardware discussion _ How Many Bad Blocks Until A Zaurus Packs It In?

Posted by: HoloVector May 9 2017, 03:59 PM

I was in the diag menu to do a NAND backup last night after the backup I decided to check the NAND Bad Count and I have 2 bad blocks out of 8. They are blocks 3 and 4. So how many more bad blocks can I before the little guy dies?

Posted by: Varti May 10 2017, 12:55 AM

Just last week I asked ant on #kexecboot about how the badblocks are handled on the NAND. I have done the same check as you on my Akita (thanksfully, no badblocks there yet), this is what he explained to me: it depends on where they are located. Mtd1 (the partition where the kernel is stored, i.e. the flashed zImage file) has all the badblocks automatically remapped to other blocks at the lower MTD level, so it doesn't matter what filesystem is used there. The first block, which is probably the first block being read at boot time, is also guaranteed to be error-free. I don't remember if the Sharp's badblocks tool prints out on what partition have been the bad blocks found, though.

Regarding the other two mtd1 and mtd2 partitions, the badblocks can be only handled by the used filesystem. The standard jffs1/2 filesystem, used by Cacko and pdaXrom, doesn't have such a feature, but there might exist a tool which checks and remaps them. Ubifs handles them, but it is not supported by neither Cacko or pdaXrom; only kexecboot and (I believe) OE's Poky can be run on this filesystem.

If the badblocks are within mtd2 or 3, it might be a good idea to boot Cacko from SD instead of NAND.

Varti

Powered by Invision Power Board (http://www.invisionboard.com)
© Invision Power Services (http://www.invisionpower.com)