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Thread: Can't format EXT4 flash drive correctly - superblock errors

  1. #1
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    Can't format EXT4 flash drive correctly - superblock errors

    Hi everyone

    I've taken some time trying to solve this myself and checked the forums here pretty carefully, but if there is a thread already answering this I apologise.

    I have a 32 Gb Verbatim USB Flash drive that I want to use with a Raspberry Pi as a datalogger. Since the Pi is weedy I'm using my Ubuntu VM to format it - but no matter what I do I get superblock errors. Gparted will happily create a new a new partition table and then format the unallocated space as EXT4 - and then when it rescans for devices it puts an (i) up against my new partition and tells me that the "journal superblock magic number is invalid".

    I mooched about a bit looking at other people who have had similar issues - e2fsck doesn't seem to help.

    The drive itself is relatively new, decent brand - I don't suspect a hardware error just yet, not least because I managed to get good old Windoze to format the drive as FAT32 and it survived a pretty intense read / write speed test.

    Any help anyone can offer would be gratefully received - I don't know enough about filesystem architectures (least of all EXT4) to make any properly considered progress.

    Many thanks

    Stefan

  2. #2
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    Re: Can't format EXT4 flash drive correctly - superblock errors

    Welcome to the Ubuntu Forums

    Gparted is usually doing a good job, but sometimes you can help it with some tricks.

    1. You can start with making a new partition table. Use the pull-down menu

    Device -- Create partition table

    2. If that does not help, wipe the first megabyte of the drive (overwrite with zero)

    You can do it manually with dd (if you dare use a tool nick-named 'disk destroyer') or use mkusb described at

    Howto make USB boot drives


    And try with gparted again. If it still does not help, there is probably something wrong with the pendrive (at least it is not compatible with linux).

  3. #3
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    Re: Can't format EXT4 flash drive correctly - superblock errors

    Hi Sudodus

    Thank you for the warm welcome.

    I did as you suggested:

    sudo dd if=/dev/zero of=/dev/sdb bs=512 count=2048

    and got the following output:

    2048+0 records in
    2048+0 records out
    1048576 bytes (1.0 MB) copied, 0.207981 s, 5.0 MB/s

    Which hopefully means that my mathematics has not failed me. Sadly Gparted gives me the same reply - I create a new partition table and then a new EXT4 partition, and when it rescans I get the (i) of despair. I had never heard of a USB flash drive being incompatible with Linux before, but I'm open to new ideas!

    Thanks for the help - I might try overwriting the whole disk with zeros just to be double-sure, but perhaps it is time to consider a different approach.

    S

  4. #4
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    Re: Can't format EXT4 flash drive correctly - superblock errors

    I know little about this but it looks like you're formatting with an O.S. in a virtual machine. Would that be an issue? Perhaps create a live CD/DVD/USB and try formatting with that? Again, I'm not knowledgeable about this, just thinking what I'd try.

  5. #5
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    Re: Can't format EXT4 flash drive correctly - superblock errors

    Quote Originally Posted by stefan.dzisiewski. View Post
    Hi Sudodus

    Thank you for the warm welcome.

    I did as you suggested:

    sudo dd if=/dev/zero of=/dev/sdb bs=512 count=2048

    and got the following output:

    2048+0 records in
    2048+0 records out
    1048576 bytes (1.0 MB) copied, 0.207981 s, 5.0 MB/s

    Which hopefully means that my mathematics has not failed me. Sadly Gparted gives me the same reply - I create a new partition table and then a new EXT4 partition, and when it rescans I get the (i) of despair. I had never heard of a USB flash drive being incompatible with Linux before, but I'm open to new ideas!

    Thanks for the help - I might try overwriting the whole disk with zeros just to be double-sure, but perhaps it is time to consider a different approach.

    S
    Yes, you have overwritten the first megabyte, so any traces, that might confuse gparted should be gone.

    What happens if you un-plug the pendrive and re-plug it again? Will it be recognized properly? Or try in another computer, if the problem might be the USB hardware in that computer?

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