[ltp] SD cards always mount read-only

[John Jason Jordan]

Fedora 14, x86_64 on Lenovo Thinkpad T61.

About six months ago I bought a Transcend 32 GB SD card for my (then)
new Android phone. Foolishly I bought the mini size, not the micro
size. Before returning it I tried it in my T61, only to discover
that it mounted read-only. I tried various things (now forgotten), but
failed to get it to mount read-write. Since it was the wrong size for
the phone I just returned it to Amazon.

Then I bought a Transcend 32 GB micro SD card that came with an
adapter. Again, I tried to mount it in the laptop, but it also mounted
read-only. But when I put it in the phone I had no problems - Android
happily mounted it read-write. I continue to use it in the phone.

The other day I found a deal on a Sandisk 32 GB micro SD card, so I
bought it. Like the Transcend, it came with an adapter. My plan was to
use it as additional storage on the laptop. However, like its
predecessors, it mounts read-only.

To troubleshoot I started with Palimpsest. When I launched Palimpsest
at first it did not see the SD card. But after I popped the card out
and reinserted it Palimpsest automatically added it to the list of
devices. And Nautilus automatically opened a file browser window
(although still read-only).

Palimpsest reported the following potentially useful information:

DRIVE:

    * Model: 			SU32G
    * Firmware version: 	12/2010
    * Location			-
    * Write cache		-
    * Capacity: 			32 GB
    * Partitioning: 		Master boot record
    * Serial number: 		0c38530e
    * World wide name	-
    * Device: 			/dev/mmcblk0
    * Rotation rate: 		Solid state disk
    * Connection: 		SDIO
    * Smart status 		Not supported

In the DRIVE section Palimpsest offers buttons for Format Drive, and
for Benchmark.

VOLUMES:

    * Usage: 			Filesystem
    * Partition type:		W95 FAT32 (LBA) (0x0c)
    * Partition flags: 		Bootable
    * Label				-
    * Type: 			FAT (32 bit version)
    * Device: 			/dev/mmcblk0p1
    * Partition label: 		-
    * Capacity: 			32 GB
    * Available: 			-
    * Mount point: 		Mounted at /media/SD

In the VOLUME section Palimpsest offers buttons for Unmount Volume,
Check Filesystem, Delete Partition, Format Volume, and Edit Partition.

I tried every button on the Palimpsest window, but all failed with an
error message that the drive was read-only.

I tried GParted (which requires root access to open) but, again, I was
unable to change anything. GParted gave me essentially the same error
messages - that the drive was read-only so it could not change
anything. I even tried deleting the partition, but that also failed.

Note that this card will be used only for additional storage, so it
does not need to be bootable.

Next I created a mount point at /media/SD, then I tried adding it
to /etc/fstab. My first attempt in fstab was:

/dev/mmcblk0 /media/SD vfat noauto,users,rw 0 0

But that always generated error messages that /dev/mmcblk0 did not
exist. So, armed with the information from Palimpsest I changed it to:

/dev/mmcblk0p1 /media/SD vfat noauto,users,rw 0 0

That line works. That is, it mounts now at /media/SD, but it still
mounts read-only. Here is what the mount command reports:

[root@Devil8 SD]# mount
/dev/mmcblk0p1 on /media/SD type vfat (ro,noexec,nosuid,nodev)

I have tried mkfs, fsck (no errors), and dmesg. After popping it out
and  back in again, from dmesg I get:

[root@Devil8 SD]# dmesg | tail
[11614.649373] mmc0: card e624 removed 
[11714.619488] mmc0: error -110 whilst initialising SD card
[11744.034320] mmc0: new high speed SDHC card at address e624
[11744.034572] mmcblk0: mmc0:e624 SU32G 29.7 GiB (ro) 
[11744.034823] mmcblk0: p1

I need some super-root command that will delete the partition or allow
me to reformat it. 

I also need feedback from other T61 users. Has anyone else experienced
this with an SD card on a T61? If so, is there a solution? If you have
an SD card on a T61 that works read-write, can you give me some details
about your distro, brand of SD card, etc.?

Any and all suggestions are welcome!