> > Does you SD card and/or SD card adapter have a write-protect tab or other > such mechanism? If so, put it in the unlocked position.
The micro SD cards used in phones don't appear to have such mechanisms, but your point is well taken; viz. I've not adequately checked the hardware path (MB, card reader, etc. red-faced here...) > > Have you tried using dd to wipe the first megabyte (including the partition > table)? > > # dd if=/dev/zero of=/dev/sdc count=2048; sync > Yes, but no effect. Even count=1 gets to non-zero bytes: dd if=/dev/sdc count=1 | od -b 0000000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 * 0000700 002 000 356 377 377 377 001 000 000 000 377 043 267 003 000 000 0000720 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 * 0000760 000 000 000 000 000 000 000 000 000 000 000 000 000 000 125 252 1+0 records in 1+0 records out 0001000 512 bytes (512 B) copied, 0.00365101 s, 140 kB/s dd if=/dev/zero of=/dev/sdc count=1; sync 1+0 records in 1+0 records out 512 bytes (512 B) copied, 0.0170507 s, 30.0 kB/s dd if=/dev/sdc count=1 | od -b 0000000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 * 0000700 002 000 356 377 377 377 001 000 000 000 377 043 267 003 000 000 0000720 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 * 0000760 000 000 000 000 000 000 000 000 000 000 000 000 000 000 125 252 , 0.00290682 s, 176 kB/s 1+0 records in 1+0 records out 512 bytes (512 B) copied 0001000 Maybe I'm not looking at this right... The idea that a card could be locked up by the OS is titillating but improbable. There would have to be an (apparently) unpublished trap door or a back door to the disk controller in a generic disk. So it's gotta be hardware and this has all been noise.
