[SOLVED] Could I broke my SD card with badblocks or dd? [I coudn't]

Question

I found some old, 1GB SD Card and wanted to use it as my EFI partition (well, wanted to check if my EFI system will even see it as I have no idea if it's possible or not). There were some old pictures so I thought - okay, it's working. I've wiped it with
badblocks -wsv
and the final output was
Pass completed, 216640 bad blocks found. (0/0/216640 errors)
which seems to me like ALL blocks are "bad" (corruption error). Well, I thought that maybe badblocks wasn't created to check SD cards. I then used gdisk to get:
Command (? for help): p
Disk /dev/mmcblk0: 1984000 sectors, 968.8 MiB
Logical sector size: 512 bytes
Disk identifier (GUID): 84DBE3FD-1D8A-4E49-80D1-9F9594BB1974
Partition table holds up to 128 entries
First usable sector is 34, last usable sector is 1983966
Partitions will be aligned on 2048-sector boundaries
Total free space is 8158 sectors (4.0 MiB)
Number  Start (sector)    End (sector)  Size       Code  Name
   1            8192         1983966   964.7 MiB   EF00  EFI System
After writing changes to the card (
Command (? for help): w
Final checks complete. About to write GPT data. THIS WILL OVERWRITE EXISTING
PARTITIONS!!
Do you want to proceed? (Y/N): y
OK; writing new GUID partition table (GPT) to /dev/mmcblk0.
The operation has completed successfully.
) I saw no extra partition in my /dev so I ran gdisk again and it prompted:
Caution: invalid main GPT header, but valid backup; regenerating main header
from backup!
Caution! After loading partitions, the CRC doesn't check out!
Warning! Main partition table CRC mismatch! Loaded backup partition table
instead of main partition table!
Warning! One or more CRCs don't match. You should repair the disk!
Partition table scan:
  MBR: protective
  BSD: not present
  APM: not present
  GPT: damaged
Caution: Found protective or hybrid MBR and corrupt GPT. Using GPT, but disk
verification and recovery are STRONGLY recommended.
I've tried to
dd if=/dev/urandom
too and all the other options I could think of, just to start over... but... it is just broken now? Was it broken before?
Last edited by smsware (2013-07-17 11:57:24)

Answer 1

It was in some old phone of mine and appears to be as clean as brand new. But
sudo dcfldd if=/dev/urandom of=/dev/mmcblk0 bs=4M count=1
gave
1+0 records in
1+0 records out
as an output so I actually can write into it, right? I played a little with the lock label but it's acting the same. If lock label is set to protect the data, the output is
dcfldd:/dev/mmcblk0: Read-only file system
so it's not the problem. I want to buy new card anyway but I just want to be sure that I will not broke it too. ;-)
I've found this:
The SD/SDHC/SDXC memory cards have a "Protected Area" on the card for the SD standard's security function. The SD Formatter does not format the "Protected Area".
and also (but can't find it again to quote) that you should leave first 8192 sectors (blocks? I'm really bad with hardware) free of modification because the performance would be worse then (but no information about braking it!).