MicroSD partition (FAT32) is unkillable

madchine · 2011-11-20 13:56:37

The problem

My 32 GB microSD card (FAT32) is currently in a state where nothing I do to it takes effect. Reading is not a problem.

Specifically, I cannot add any files, delete any files and more importantly I cannot delete the FAT32 partition. In fact, dd'ing the drive (the first 446 blocks or the entire drive) doesn't accomplish anything either.

My attempts

Let me be precise: I can perform any of these actions and to some extent the system plays along. Yes, I am allowed to delete all the files and it looks like they are gone. The point is that, nothing really happens. Remove the drive and reinsert it and the files are back, the partition is still there and so on.

An example: Using Gparted to delete the partition and write another on top it, will result in failure on the second job. Gparted believes it has succeeded in the first job, but trying to write the new partition it realizes that the old one is still there.

My searching for solution suggested that a physical lock might prevent writing to the drive. I looked at the drive and found none. There was however a lock switch on an SD card 'shell' that would allow my microSD card to go in an SD card reader. Employing this causes the drive to react in a different manner, actvely refusing any write/delete attempts.

Apart from these linux maneuvers, I have tried letting both Android and Windows format the drive with no more success. The partition seems unkillable.

Context

The drive has primarily been used in my Android phone (a Samsung Galaxy S running Android 2.3.3 aka Gingerbread) but for transfes it has connected to my Linux as well as my Windows Vista laptop. This has been done using the MSC connection option either the phone or my Sansa Clip+ MP3 player, serving as card reader.

I have no explanation for what has happened. I have a very vague recollection that the problem might have coincided with changing the drive labels case, e.g. from 'interzone' to 'INTERZONE', possibly on the Vista laptop, or omething like that. It was during a very hectic exam period and so I haven't had time to follow up on it until now.

This is what DMESG says when the drive is inserted:

[150125.326513] sd 2:0:0:0: [sdb] 62333952 512-byte logical blocks: (31.9 GB/29.7 GiB)
[150125.327509] sd 2:0:0:0: [sdb] No Caching mode page present
[150125.327758] sd 2:0:0:0: [sdb] Assuming drive cache: write through
[150125.330128] sd 2:0:0:0: [sdb] No Caching mode page present
[150125.330364] sd 2:0:0:0: [sdb] Assuming drive cache: write through
[150125.343845]  sdb: sdb1

I am grateful for any assistance.

Last edited by madchine (2011-11-20 13:57:32)

Arch Linux

#1 2011-11-20 13:56:37