LinuxQuestions.org - SD Card Read only Weirdness.

My Android w/CM-6.0 went a bit belly up recently, and one of the funny things it did was make all the sd cards I used in it read only to pcs, although it could read/write them OK. Observe the following

Code:

su

Password: 

bash-4.1# umount /dev/sdb1

bash-4.1# umount /dev/sdb2

umount: /dev/sdb2: not mounted

bash-4.1# fdisk /dev/sdb

You will not be able to write the partition table.[###:-O??]



Command (m for help): p



Disk /dev/sdb: 1995 MB, 1995440128 bytes

64 heads, 63 sectors/track, 966 cylinders, total 3897344 sectors

Units = sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 512 bytes

I/O size (minimum/optimal): 512 bytes / 512 bytes

Disk identifier: 0x000caf3b



  Device Boot      Start        End      Blocks  Id  System

/dev/sdb1            131    1943359      971614+  6  FAT16

/dev/sdb2        1951488    3894911      971712  83  Linux

I am new to fdisk with root permissions being shoved aside and told it's read only. So I got even more drastic

Code:

bash-4.1# dd if=/dev/zero of=/dev/sdb bs=512 count=3897344

dd: opening `/dev/sdb': Read-only file system

bash-4.1# shred /dev/sdb

shred: /dev/sdb: failed to open for writing: Read-only file system

bash-4.1#

This one is 2 gig, value near zero. I also have a 4G and a 16G. The Android seems to have no difficulty. I'm talking to the sdcard atm via an sdcard reader which did not previously exhibit this behaviour.

Any other ideas??