Problems reading micro SD card

I'm having trouble accessing my Samsung 128GB micro SDXC card.
My Lenovo Legion Y520 laptop is running dual boot with Windows 10 and Manjaro KDE.
Windows recognises and reads the card without problems.
On Manjaro the card is recognised in the partition manager but it says that "No valid partition table was found on this device".

I also tried to mount it manually:

sudo mount /dev/mmcblk0 /mnt/sdcard/
mount: /mnt/sdcard: can't read superblock on /dev/mmcblk0.

The card is formatted in ExFat and I do have exfat-utils installed.

The laptop doesn't have a micro sd card reader but it does have a normal sd card reader so I'm using a micro sd to sd adapter.

Do you have realy all exfat tools installed?

As far I am aware of.
I just got exfat-utils installed.
Are there other tools necessary?

So! I'm back.:grin:
The error message which you see

means something like : "no driver for exfat installed...". And this can be the problem with your partitionmanager.

In the AUR is a package "exfat-utils-autodetect". Tried?

A little bit "Fast Forward":

You can also save all data of the card and try format the card with "exfat" in Manjaro. It could be the card is "Windows specific" formated....
If you use it only in Linux and Windows then you can also format with "Ntfs". But format the card in Windows with "Ntfs".

I tried it but it made no difference.

So I tried formatting the card in Manjaro but I couldn't even get to that step because I apparantly also can't create a partition table.
Output from the partition manager:

Create a new partition table (type: msdos) on ‘/dev/mmcblk0’
  Job: Create new partition table on device ‘/dev/mmcblk0’
    Command: sfdisk /dev/mmcblk0
  Create new partition table on device ‘/dev/mmcblk0’: Error
Create a new partition table (type: msdos) on ‘/dev/mmcblk0’: Error

Output from parted:

sudo parted /dev/mmcblk0 
(parted) mklabel msdos
Error: Input/output error during read on /dev/mmcblk0

So I tried formatting the card in Windows with exfat and try again. I got the same result.
I thought maybe Manjaro would recognise the card when it was formatted with NTFS.
So I formatted it again in Windows with NTFS but I still get the same problem with no partition table being found and not being able to create a new partition table.

The card is still working perfectly in windows.


I went and checked, but my camera that I intend to use the card with doesn't seem to like NTFS very much. It just doesn't seem to recognise the card.

Have you tried a little magic like "dd" in terminal?

If not:
"dd if=/dev/zero of=/dev/<your_card> count=10000"
It will write some nulldata on the card if it works. But its dangerous! It could be the card is after this no more functional. But if you try this and "dd" dont break with error then you know the card works in linux..... But its dangerous!

For you camera the card has to be formated by the camera to work not by anything else.

Bad superblock = corrupted partition.

Fix it with Linux, not that other OS.


If it could completely break the card I would want to keep this as a last resort.

The camera I use is not able to format the card itself. It just uses a SD card formatted with exfat.

As you can see in my previous message I am having a bit of problems with doing just that. Could you give me some further directions please?

I think the card doesnt works with Linux but im not sure. The card works differently than a SDHC-Card (works but no 4k support).

You can try a new kernel or ask the "gparted" developer why it not work or ask Samsung support or ... try a USB- Cardreader or ... try the card in a Android Smartphone. :thinking:

Apparently the fix was this easy.
I was on 4.19. On 5.1 the SD card is recognised and works perfectly.

Thanks a lot!

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