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I changed the filesystem format of my SD card to NTFS so applications on my system to write to it. I couldn't access it anymore, so I changed it back to FAT, but I still can't access it as root, or regular user. As root, it doesn't list. As for accessing with user, I get an error pop-up, which reads "Unable to access 32 GB Volume, not authorized to perform operation."

The df command gives me the following output:

Filesystem                     1K-blocks    Used Available Use% Mounted on
/dev/mmcblk0p1                  10732080 8523064   1640800  84% /
devtmpfs                          995380       0    995380   0% /dev
shmfs                             997360   52396    944964   6% /dev/shm
tmp                               997360   19924    977436   2% /tmp
tmpfs                             199476      56    199420   1% /run
tmpfs                               5120       0      5120   0% /run/lock
run                               997360     448    996912   1% /var/host/dbus
/dev/mapper/encstateful          3164880  139276   3009220   5% /var/host/timezone
/dev/root                        1763840 1583608    180232  90% /lib/modules/3.18.0-13527-gc2f2230
media                             997360       4    997356   1% /var/host/media
/home/.shadow/dbb3045.../vault  10732080 8523064   1640800  84% /home/friskybits/Downloads
none                              997360       0    997360   0% /sys/fs/cgroup
none                              997360       4

The sudo lsblk -f command gives me the following output:

NAME                 FSTYPE   LABEL      MOUNTPOINT
loop0                                    
└─encstateful (dm-1) ext4                
loop1                squashfs            
loop2                squashfs            
loop3                squashfs            
loop4                squashfs            
loop5                squashfs            
loop6                squashfs            
zram0                                    [SWAP]
mmcblk0rpmb                              
mmcblk0boot0                             
mmcblk0boot1                             
mmcblk0                                  
├─mmcblk0p1          ext4                
├─mmcblk0p2                              
├─mmcblk0p3          ext4     ROOT-A     
│ └─vroot (dm-0)                         
├─mmcblk0p4                              
├─mmcblk0p5          ext4     ROOT-A     
├─mmcblk0p6                              
├─mmcblk0p7                              
├─mmcblk0p8          ext4     OEM        
├─mmcblk0p9                              
├─mmcblk0p10                             
├─mmcblk0p11                             
└─mmcblk0p12         vfat     EFI-SYSTEM 
mmcblk1                                  
└─mmcblk1p1          vfat

The sudo lsblk -m command gives me the following output:

NAME                   SIZE OWNER GROUP MODE
loop0                  3.1G root  disk  brw-rw----
└─encstateful (dm-1)   3.1G root  root  brw-------
loop1                397.5M root  disk  brw-rw----
loop2                 48.8M root  disk  brw-rw----
loop3                    4K root  disk  brw-rw----
loop4                    4K root  disk  brw-rw----
loop5                    4K root  disk  brw-rw----
loop6                    4K root  disk  brw-rw----
zram0                  2.8G root  disk  brw-rw----
mmcblk0rpmb              4M root  disk  brw-rw----
mmcblk0boot0             4M root  disk  brw-rw----
mmcblk0boot1             4M root  disk  brw-rw----
mmcblk0               14.7G root  disk  brw-rw----
├─mmcblk0p1           10.5G root  disk  brw-rw----
├─mmcblk0p2             16M root  disk  brw-rw----
├─mmcblk0p3              2G root  disk  brw-rw----
│ └─vroot (dm-0)       1.7G root  root  ---------
├─mmcblk0p4             16M root  disk  brw-rw----
├─mmcblk0p5              2G root  disk  brw-rw----
├─mmcblk0p6            512B root  disk  brw-rw----
├─mmcblk0p7            512B root  disk  brw-rw----
├─mmcblk0p8             16M root  disk  brw-rw----
├─mmcblk0p9            512B root  disk  brw-rw----
├─mmcblk0p10           512B root  disk  brw-rw----
├─mmcblk0p11             8M root  disk  brw-rw----
└─mmcblk0p12            16M root  disk  brw-rw----
mmcblk1               29.7G root  disk  brw-rw----
└─mmcblk1p1           29.7G root  disk  brw-rw----

And the sudo parted -ls command gives me the following output:

Model: Linux device-mapper (crypt) (dm)
Disk /dev/mapper/encstateful: 3297MB
Sector size (logical/physical): 512B/512B
Partition Table: loop

Number  Start  End     Size    File system  Flags
 1      0.00B  3297MB  3297MB  ext4


Error: /dev/mmcblk0rpmb: unrecognised disk label
Warning: Error fsyncing/closing /dev/mmcblk0rpmb: Input/output error

Error: /dev/mmcblk0boot0: unrecognised disk label

Error: /dev/mmcblk0boot1: unrecognised disk label

Model: MMC 400073 (sd/mmc)
Disk /dev/mmcblk0: 15.8GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt

Number  Start   End     Size    File system  Name        Flags
11      32.8kB  8421kB  8389kB               RWFW
 6      8421kB  8422kB  512B                 KERN-C
 7      8422kB  8422kB  512B                 ROOT-C
 9      8422kB  8423kB  512B                 reserved
10      8423kB  8423kB  512B                 reserved
 2      10.5MB  27.3MB  16.8MB               KERN-A
 4      27.3MB  44.0MB  16.8MB               KERN-B
 8      44.0MB  60.8MB  16.8MB  ext4         OEM         msftdata
12      128MB   145MB   16.8MB  fat16        EFI-SYSTEM  boot
 5      145MB   2292MB  2147MB  ext2         ROOT-B
 3      2292MB  4440MB  2147MB  ext2         ROOT-A
 1      4440MB  15.7GB  11.3GB  ext4         STATE       msftdata


Warning: /dev/mmcblk1 contains GPT signatures, indicating that it has a GPT table.  However, it does not have a valid fake msdos partition table, as it should.  Perhaps it was corrupted -- possibly by a program that doesn't understand GPT partition tables.  Or perhaps you deleted the GPT table, and are now using an msdos partition table.  Is this a GPT partition table?
Error: The backup GPT table is corrupt, but the primary appears OK, so that will be used.
Model: SD SS32G (sd/mmc)
Disk /dev/mmcblk1: 31.9GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt

Number  Start   End     Size    File system  Name        Flags
11      32.8kB  8421kB  8389kB               RWFW
 6      8421kB  8422kB  512B                 KERN-C
 7      8422kB  8422kB  512B                 ROOT-C
 9      8422kB  8423kB  512B                 reserved
10      8423kB  8423kB  512B                 reserved
 2      10.5MB  27.3MB  16.8MB               KERN-A
 4      27.3MB  44.0MB  16.8MB               KERN-B
 8      44.0MB  60.8MB  16.8MB               OEM         msftdata
12      128MB   145MB   16.8MB               EFI-SYSTEM  boot
 5      145MB   147MB   2097kB               ROOT-B
 3      147MB   2244MB  2097MB               ROOT-A
 1      2244MB  2263MB  18.9MB               STATE       msftdata

How can I access the SD card?

sudodus
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giikae
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  • Please run the following terminal window commands (when the SD card is plugged in) and edit your question to add the output of the commands. It will help us help you. df; sudo lsblk -f; sudo lsblk -m; sudo parted -ls - You can copy and paste from the terminal window to the edit window of AskUbuntu. – sudodus Feb 18 '17 at 05:09
  • This does not look like a standard computer booted from an internal drive. It seems to be booted from one [SD (?)] card mmcblk0. And it sees another card mmcblk1 but parted omplains about it. Please describe what computer it is, what operating system and how it was installed. Finally please describe how you edited the problematic SD card in order to change it back to FAT. – sudodus Feb 18 '17 at 05:35
  • @sudodus My "computer" is a Samsung Chromebook 3, and it obviously, because it's a chromebook, runs ChromeOS. I installed Ubuntu via Crouton, so that may be why it does not look like a standard Ubuntu system, but mmcblk0 is actually the internal eMMC storage. mmcblk1 is my SD card. I forgot to unmount the SD card before I changed the filesystem type, so that is why it is corrupted. – giikae Feb 18 '17 at 07:59

2 Answers2

2

Mount a FAT32 partition in an SD card with write permissions for everybody

(assumption: the SD card is seen as /dev/mmcblk1, replace mmcblk1p1 with the actual letters for the partition, for example sdb1 if a USB pendrive or an SD card connected via USB, /dev/mmcblk1p1 ---> /dev/sdb1)

sudo mkdir -p /mnt/sd1  # only if you want a new mountpoint
sudo umount /dev/mmcblk1p1   # only if already mounted (but with bad permissions)

sudo mount -o rw,users,umask=000 /dev/mmcblk1p1 /mnt/sd1  # mount

or (if connected via USB)

sudo mkdir -p /mnt/sd1  # only if you want a new mountpoint
sudo umount /dev/sdb1   # only if already mounted (but with bad permissions)

sudo mount -o rw,users,umask=000 /dev/sdb1 /mnt/sd1  # mount

Check permissions

ls -ld /mnt/sd1

Test

sudo bash -c "echo 'Hello World' > /mnt/sd1/hello.txt"  # test writing with sudo
cat /mnt/sd1/hello.txt                   # test reading (as user)
ls -l /mnt/sd1                           # check permissions of the content
rm /mnt/sd1/hello.txt                    # test removing (as user)
echo 'I am a user' > /mnt/sd1/user.txt   # test writing (as user)

Edit: Different umask alternatives are illustrated with the following command lines, in this case assuming device /dev/sdb1

$ sudo umount /mnt/sd1; sudo mount -o rw,users,umask=077 /dev/sdb1 /mnt/sd1;ls -ld /mnt/sd1
drwx------ 2 root root 4096 jan  1  1970 /mnt/sd1  # only root has permissions
$ sudo umount /mnt/sd1; sudo mount -o rw,users,umask=033 /dev/sdb1 /mnt/sd1;ls -ld /mnt/sd1
drwxr--r-- 2 root root 4096 jan  1  1970 /mnt/sd1  # users have read permissions
$ sudo umount /mnt/sd1; sudo mount -o rw,users,umask=022 /dev/sdb1 /mnt/sd1;ls -ld /mnt/sd1
drwxr-xr-x 2 root root 4096 jan  1  1970 /mnt/sd1  # users have read and execute permissions
$ sudo umount /mnt/sd1; sudo mount -o rw,users,umask=011 /dev/sdb1 /mnt/sd1;ls -ld /mnt/sd1
drwxrw-rw- 2 root root 4096 jan  1  1970 /mnt/sd1  # users have read and write permissions
$ sudo umount /mnt/sd1; sudo mount -o rw,users,umask=000 /dev/sdb1 /mnt/sd1;ls -ld /mnt/sd1
drwxrwxrwx 2 root root 4096 jan  1  1970 /mnt/sd1  # users have full permissions

If this does not work

If this does not work, you may find a solution or at least an explanation at the following link,

Can't format my usb drive. I have already tried with mkdosfs and gparted: Analysis of the problem

sudodus
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0

It sounds like you already have some application open which has the SD card mounted, blocking root/user from mounting it. Check if gparted has it open.

goldenlinx
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