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Found this in the logs

Discussion in 'Tomato Firmware' started by Mercjoe, Aug 31, 2014.

  1. Mercjoe

    Mercjoe Network Guru Member

    I flashed Shibby 122 on my R7000. in reviewing the logs I found this:


    Dec 31 19:01:26 ARMtomato kern.info kernel: Scanning device for bad blocks
    Dec 31 19:01:26 ARMtomato kern.warn kernel: Bad eraseblock 801 at 0x000006420000
    Dec 31 19:01:26 ARMtomato kern.warn kernel: Bad eraseblock 952 at 0x000007700000

    Anyone have any ideas on this?
     
  2. koitsu

    koitsu Network Guru Member

    Not really all that surprising. Reading material (which must be read in full):

    http://lists.infradead.org/pipermail/linux-mtd/2006-August/016253.html
    http://wiki.openmoko.org/wiki/NAND_bad_blocks#Bad_Blocks (just this section)
    http://forums.hardwarezone.com.sg/i...clinic-4/bad-eraseblock-rt-ac68u-4408942.html

    With regards to the 2nd link, what the above indicates is that the kernel is aware of NAND pages which can no longer be reliably used, thus it avoids them. Google "bad eraseblock" and you'll see lots of NAND-based devices (not just routers) going through this. They are probably factory defaults, but it's hard to say for sure (there is simply no way to get the low-level details from the NAND controller itself).

    With regards to the 3rd link, you can clearly see the Asus stating the device should be RMAd. Welcome to today's technology.

    If you don't want to RMA right now, no problem. What you need to do is keep an eye on it. If the number begins to increase (more bad eraseblock messages than just 2, especially if it begins increasing rapidly, say going from 2 to maybe 12 or 14 -- this is just arbitrary and it's up to you to decide what's too much), then you should consider RMA'ing the router with either the place of purchase or with Netgear. It simply means your NAND flash is wearing out (nothing you did may be the source of the problem, it may simply be the flash installed on your particular device was cheap, unreliable, or just went bad over time**. They shouldn't give you any lip over it.

    ** -- NAND sucks in this regard, big time, which should make you question just how wise it was for vendors to go with NAND for SSDs, and even more crazy things like TLC NAND. Memristors are a better choice altogether, but everyone decided to cheap out.
     
  3. Mercjoe

    Mercjoe Network Guru Member

    Thanks for the reply. I goggled it before posting and saw lots of references but no exact reasoning. I figured it was like a bad block on a SSD.
     
  4. koitsu

    koitsu Network Guru Member

    There's no SSD involved here -- this is purely NAND flash on the router, meaning it's in reference to the flash region (where your firmware gets written to). SSDs do use NAND, just a slightly different type of it.
     

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