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View Full Version : [SOLVED] 32 gb micro sdhc card corrupt, "unknown partition table"



limescout
April 12th, 2011, 04:51 AM
Hello all,
I recently received a 32gb micro sdhc card for storing music on my phone. I first formatted the card on my phone for use with it's music player. Then I inserted the card into my computer's sd slot. I began to copy music to the card, but it froze during a file sample. I couldn't force quit the process, so I shut down ubuntu thinking I'll reformat the card and start again. Something went wrong with the card and I don't know what to do about it.

My phone won't recognize the card like it did before. It behaves as if there is no card.

Windows shows the card, but when I try to format it in Windows, it gives me an error; something like "windows could not format the drive"

Here is what I get from dmesg:

[ 215.780234] mmc0: new SD card at address 0001
[ 215.780490] mmcblk0: mmc0:0001 AF HM 8.00 MiB
[ 215.780616] mmcblk0: unknown partition table


please don't hesitate to ask for any more information.

dandnsmith
April 12th, 2011, 12:43 PM
I'd be tempted to dd /dev/zero to the first 512 bytes to scrub the partition and other info, and then check if the phone can now 'see' it.

Grenage
April 12th, 2011, 12:50 PM
Hello all,
I recently received a 32gb micro sdhc card for storing music on my phone. I first formatted the card on my phone for use with it's music player. Then I inserted the card into my computer's sd slot. I began to copy music to the card, but it froze during a file sample. I couldn't force quit the process, so I shut down ubuntu thinking I'll reformat the card and start again. Something went wrong with the card and I don't know what to do about it.

My phone won't recognize the card like it did before. It behaves as if there is no card.

Windows shows the card, but when I try to format it in Windows, it gives me an error; something like "windows could not format the drive"

Here is what I get from dmesg:

[ 215.780234] mmc0: new SD card at address 0001
[ 215.780490] mmcblk0: mmc0:0001 AF HM 8.00 MiB
[ 215.780616] mmcblk0: unknown partition table


please don't hesitate to ask for any more information.

32GB Ebay purchase, so cheap it seemed too good to be true?

What does
sudo fdisk -l tell you?

limescout
April 12th, 2011, 09:26 PM
relevant info from "fdisk -l"

Disk /dev/mmcblk0: 8 MB, 8388608 bytes
4 heads, 16 sectors/track, 256 cylinders
Units = cylinders of 64 * 512 = 32768 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xe846a429

Disk /dev/mmcblk0 doesn't contain a valid partition table


sudo dd if=/dev/zero of=/dev/mmcblk0 bs=512

$ sudo dd if=/dev/zero of=/dev/mmcblk0 bs=512
dd: writing `/dev/mmcblk0': No space left on device
16385+0 records in
16384+0 records out
8388608 bytes (8.4 MB) copied, 2.85786 s, 2.9 MB/s
$


card is still not recognized on phone or computer

coffeecat
April 12th, 2011, 10:46 PM
card is still not recognized on phone or computer

When you say not recognised on computer, does fdisk still see it, albeit with no partition table? If you get:


Disk identifier: 0x00000000

Try seeing if you can create a new partition table in Gparted (from the device menu) and then a formatted partition.

limescout
April 13th, 2011, 05:56 AM
It won't show up in Gparted at all

I've been reading up lately about fake memory cards, and I'm convinced this is one of them. The place where I bought it is going to give me a full refund, so I think I'm going to just return it and get one from a different company. Thanks for your suggestions everyone.

Grenage
April 13th, 2011, 08:39 AM
It won't show up in Gparted at all

I've been reading up lately about fake memory cards, and I'm convinced this is one of them. The place where I bought it is going to give me a full refund, so I think I'm going to just return it and get one from a different company. Thanks for your suggestions everyone.

Yes, that was and is my suspicion; there have been a lot of people coming here with '8GB+' drives.