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I have a SD card that has some issues and I could not fixed them.
This is how the disk looks like in GNOME Disks: Ubuntu Disks

When I run gdisk /dev/sdb, it gives the following output:

sudo gdisk /dev/sdb
GPT fdisk (gdisk) version 1.0.3

Caution: invalid backup GPT header, but valid main header; regenerating
backup header from main header.

Warning! Main and backup partition tables differ! Use the 'c' and 'e' options
on the recovery & transformation menu to examine the two tables.
Warning! One or more CRCs don't match. You should repair the disk!

Partition table scan:
MBR: hybrid
BSD: not present
APM: not present
GPT: damaged

Found valid MBR and corrupt GPT. Which do you want to use? (Using the
GPT MAY permit recovery of GPT data.

I am not sure which partition table should I use but I used GPT (create blank GPT was not helpful) This is how the partitions are look like:

Command (? for help): p
Disk /dev/sdb: 125067264 sectors, 59.6 GiB
Model: Multi-Card      
Sector size (logical/physical): 512/512 bytes
Disk identifier (GUID): 76A0F070-E171-475B-9409-53840D61AD12
Partition table holds up to 128 entries
Main partition table begins at sector 2 and ends at sector 33
First usable sector is 34, last usable sector is 4194270
Partitions will be aligned on 2048-sector boundaries
Total free space is 671677 sectors (328.0 MiB)


Number  Start (sector)    End (sector)  Size       Code  Name
1            2048           67583   32.0 MiB    0C01  hassos-boot
2           67584          116735   24.0 MiB    8300  hassos-kernel0
3          116736          641023   256.0 MiB   8300  hassos-system0
4          641024          690175   24.0 MiB    8300  hassos-kernel1
5          690176         1214463   256.0 MiB   8300  hassos-system1
6         1214464         1230847   8.0 MiB     8300  hassos-bootstate
7         1230848         1427455   96.0 MiB    8300  hassos-overlay
8         1427456         3524607   1024.0 MiB  8300  hassos-data

I will get this Info when I want to verify the disk:

Caution: The CRC for the backup partition table is invalid. This table may
be corrupt. This program will automatically create a new backup partition
table when you save your partitions.

Problem: The secondary header's self-pointer indicates that it does not reside
at the end of the disk. If you've added a disk to a RAID array, use the 'e'
option on the experts' menu to adjust the secondary header's and partition
table's locations.

Identified 2 problems!

I could managed to fix these problems and then I got this massage:

No problems found. 121544637 free sectors (58.0 GiB) available in 2
segments, the largest of which is 121542623 (58.0 GiB) in size.

but after writing I got this:

 OK: writing new GUID partition table (GPT) to /dev/sdb.
 The operation has completed successfully.

But when I check the partitions again, it is still the same. I have tried to delete all partitions one by one and then create a new empty GUID partition table but after writing I got this:

OK: writing new GUID partition table (GPT) to /dev/sdb.
The operation has completed successfully.

But when I check the partitions again, it is still the same. I think it is because of the of hybrid MBR and damaged GPT. Is there any way to delete both of these tables at the same time? Or what can I still do to fix this problem?

Thanks in advance

1 Answer 1

0

I actually had this same problem recently. Your SD card may be in some kind of write-protected mode. Possible causes:

  1. The flash memory has worn out and can't be written to anymore. (This is bad!)
  2. The physical write-protection switch may be enabled. (Switch it off to enable writing again.)

In my case, the flash disk controller was silently discarding my writes after the flash memory failed, so even though the writes looked successful, the corrupted partition table came back on the next read.

If your SD card is behaving like this, it has most likely failed, and you'll need to get a new one.

I suspect that you are having the first issue because if the write-protection switch was active, you would be seeing some kind of "read-only" notice, as Linux can detect if a flash disk or SD card is write-protected. (See /var/log/syslog)

Example of a write-protected flash drive, /dev/sdc:

May 29 18:26:44 demo kernel: [32319.722491] scsi 2:0:0:0: Direct-Access     NA       NA               1.26 PQ: 0 ANSI: 5
May 29 18:26:44 demo kernel: [32319.723377] sd 2:0:0:0: Attached scsi generic sg1 type 0
May 29 18:26:44 demo kernel: [32319.724325] sd 2:0:0:0: [sdc] 31266816 512-byte logical blocks: (16.0 GB/14.9 GiB)
May 29 18:26:44 demo kernel: [32319.725131] sd 2:0:0:0: [sdc] Write Protect is on
May 29 18:26:44 demo kernel: [32319.725137] sd 2:0:0:0: [sdc] Mode Sense: 43 00 80 00
May 29 18:26:44 demo kernel: [32319.725389] sd 2:0:0:0: [sdc] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
May 29 18:26:44 demo kernel: [32319.737297]  sdc: sdc1
May 29 18:26:44 demo kernel: [32319.739266] sd 2:0:0:0: [sdc] Attached SCSI removable disk

Demo

/dev/sdb was my broken flash drive that silently discarded writes.

  1. Tried wiping out the partition table:

    root@demo [~]# gdisk /dev/sdb
    GPT fdisk (gdisk) version 1.0.3
    
    Caution: invalid backup GPT header, but valid main header; regenerating
    backup header from main header.
    
    Warning! Main and backup partition tables differ! Use the 'c' and 'e' options
    on the recovery & transformation menu to examine the two tables.
    
    Warning! One or more CRCs don't match. You should repair the disk!
    
    Partition table scan:
      MBR: hybrid
      BSD: not present
      APM: not present
      GPT: damaged
    
    Found valid MBR and corrupt GPT. Which do you want to use? (Using the
    GPT MAY permit recovery of GPT data.)
     1 - MBR
     2 - GPT
     3 - Create blank GPT
    
    Your answer: 2
    
    Command (? for help): p
    Disk /dev/sdb: 7897087 sectors, 3.8 GiB
    Model: USB Flash Disk
    Sector size (logical/physical): 512/512 bytes
    Disk identifier (GUID): 5904C65E-B410-474D-B22F-9FEA7E3582C2
    Partition table holds up to 128 entries
    Main partition table begins at sector 2 and ends at sector 33
    First usable sector is 34, last usable sector is 7897053
    Partitions will be aligned on 2048-sector boundaries
    Total free space is 2014 sectors (1007.0 KiB)
    
    Number  Start (sector)    End (sector)  Size       Code  Name
       1            2048            4095   1024.0 KiB  EF02  BIOS boot partition
       2            4096          106495   50.0 MiB    EF00  EFI System
       3          106496         7897053   3.7 GiB     8300  Linux filesystem
    
    Command (? for help): x
    
    Expert command (? for help): z
    About to wipe out GPT on /dev/sdb. Proceed? (Y/N): y
    GPT data structures destroyed! You may now partition the disk using fdisk or
    other utilities.
    Blank out MBR? (Y/N): y
    
  2. The bad partition table immediately returned:

    root@demo [~]# gdisk /dev/sdb
    GPT fdisk (gdisk) version 1.0.3
    
    Caution: invalid backup GPT header, but valid main header; regenerating
    backup header from main header.
    
    Warning! Main and backup partition tables differ! Use the 'c' and 'e' options
    on the recovery & transformation menu to examine the two tables.
    
    Warning! One or more CRCs don't match. You should repair the disk!
    
    Partition table scan:
      MBR: hybrid
      BSD: not present
      APM: not present
      GPT: damaged
    
    Found valid MBR and corrupt GPT. Which do you want to use? (Using the
    GPT MAY permit recovery of GPT data.)
     1 - MBR
     2 - GPT
     3 - Create blank GPT
    
    Your answer:
    
  3. Erasing the beginning of the disk with dd didn't have any effect, either:

    root@demo [~]# hexdump -C /dev/sdb | head
    00000000  eb 63 90 00 00 00 00 00  00 00 00 00 00 00 00 00  |.c..............|
    00000010  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
    *
    00000050  00 00 00 00 00 00 00 00  00 00 00 80 00 08 00 00  |................|
    00000060  00 00 00 00 ff fa 90 90  f6 c2 80 74 05 f6 c2 70  |...........t...p|
    00000070  74 02 b2 80 ea 79 7c 00  00 31 c0 8e d8 8e d0 bc  |t....y|..1......|
    00000080  00 20 fb a0 64 7c 3c ff  74 02 88 c2 52 bb 17 04  |. ..d|<.t...R...|
    00000090  f6 07 03 74 06 be 88 7d  e8 17 01 be 05 7c b4 41  |...t...}.....|.A|
    000000a0  bb aa 55 cd 13 5a 52 72  3d 81 fb 55 aa 75 37 83  |..U..ZRr=..U.u7.|
    000000b0  e1 01 74 32 31 c0 89 44  04 40 88 44 ff 89 44 02  |[email protected].|
    root@demo [~]# dd if=/dev/zero of=/dev/sdb bs=1M count=1 status=progress
    1+0 records in
    1+0 records out
    1048576 bytes (1.0 MB, 1.0 MiB) copied, 0.0219383 s, 47.8 MB/s
    root@demo [~]# hexdump -C /dev/sdb | head
    00000000  eb 63 90 00 00 00 00 00  00 00 00 00 00 00 00 00  |.c..............|
    00000010  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
    *
    00000050  00 00 00 00 00 00 00 00  00 00 00 80 00 08 00 00  |................|
    00000060  00 00 00 00 ff fa 90 90  f6 c2 80 74 05 f6 c2 70  |...........t...p|
    00000070  74 02 b2 80 ea 79 7c 00  00 31 c0 8e d8 8e d0 bc  |t....y|..1......|
    00000080  00 20 fb a0 64 7c 3c ff  74 02 88 c2 52 bb 17 04  |. ..d|<.t...R...|
    00000090  f6 07 03 74 06 be 88 7d  e8 17 01 be 05 7c b4 41  |...t...}.....|.A|
    000000a0  bb aa 55 cd 13 5a 52 72  3d 81 fb 55 aa 75 37 83  |..U..ZRr=..U.u7.|
    000000b0  e1 01 74 32 31 c0 89 44  04 40 88 44 ff 89 44 02  |[email protected].|
    

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