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??