Instructions I found here seem to suggest sudo dd if=/dev/zero of=/dev/disk4 bs=1 count=1024įor OSX however the difference is minor and I believe the end result should be the same.
This should overwrite the first 512 bytes of the device, thus destroying the partition table. In a terminal type: sudo dd if=/dev/zero of=/dev/disk4 bs=512 count=1 Note that I am a linux user, so I'm relying on the fact that OSX is similar, and that the same thing seems to be found for OSX on a google search.įirst we'll use dd to erase the partition table on the USB drive. I'll have a shot at removing the partition table under OSX. The errors I get under Linux don't make any more sense than this one, so I'm hoping that this is what your problem is. Delete the partition table completely and remake it, then create the new new partition as FAT and format it for good measure.
iow it's a red herring.ĭouble check that the device is not still mounted - run the unmount command again as per step 7 and double check that it really is unmounted but still accessible as a device.Ī common problem I've had with making USB boot devices under linux is an inconsistent partition table. Since it's silly that sudo (essentially 'root') can't access the device with dd it would seem that the error message "Permission denied" does not actually mean that root has a permissions problem.