6 Replies Latest reply: Oct 17, 2012 6:31 PM by a.z.p.
a.z.p. Level 1 (10 points)

I recently bought an 8 GB PC USB flash drive. One time after moving some files I pulled out the USB without ejecting it. Since then it only shows up in disk utility and I can't repair it or erase it. I don't have any valuable data on it, but it doesn't work. It has suddenly changed to RAW format and is 'write protected' according to windows when I tried to format it with Windows 7. Any help or suggestions would be greatly appreciated.

iMac, Mac OS X (10.6.8)
  • roam Level 6 (13,565 points)

    This might be worth a crack.


    Open Terminal* and find its name with;

    ls /Volumes


    Having noted its name, type.**

    chmod 775 /Volumes/itsname



    *In Terminal, a command string is typed and then one presses the return key.

    **note: there are only two spaces in that second string, either side on the number. Substitue the actual name after /Volumes/



    That should return it to a read write permission and if so you should be able to reformat it with Disk Utilitiy's 'Erase' if necessary.

  • a.z.p. Level 1 (10 points)

    The name in terminal is "USB". In Disk Utility it is called disk5s1. When I execute the command "chmod 775 /volumes/USB" nothing happens and the erase button in Disk Utility is still unclickable. So is the "Repair Disk" button in First Aid and the "Restore" button in the Restore tab of Disk Utility. When I verified the volume, it said:


    Verifying volume “disk5s1”

    ** /dev/disk5s1

    Invalid BS_jmpBoot in boot block: 000000

    Error: This disk needs to be repaired. Click Repair Disk.


    The repair button still wasn't clickable.

  • roam Level 6 (13,565 points)

    That error message "Invalid BS_jmpBoot in boot block" means the USB's firmware is corrupted, so it can't even mount to perform any operations on it.

    I think it is beyond recovery. You could try another Disk utility application like Drive Genius or Disk Warrior, but only as an academic exercise if you already own one of them, because the USB flash drive is a relatively low value item. That is a silver lining to your USB loss I suppose. 

  • a.z.p. Level 1 (10 points)

    Is there any way I can put new firmware onto it, from another USB or that I can download from the internet? And if I can, how would I apply it? I really don't care about what was on the disk, I just wan't to be able to use it again. Thanks

  • roam Level 6 (13,565 points)

    I don't know how it cold be repaired. You could try googling "Invalid BS_jmpBoot in boot block" and see what turns up.

    Keep things in perspective though. How much of your time is that flash drive worth?

  • a.z.p. Level 1 (10 points)

    I have lots of time, and i can't find the receipt, So I would be willing to take any course of action