12-25-2015 03:10 PM - edited 12-25-2015 03:14 PM
HERE IS THE ANSWER! THE STUGGLE IS OVER.
AND YES I HAVE TESTED IT. IT WORKS!!!
You can use DISKPART in Windows, or the equivalent fdisk command under Linux/Mac.
Start a command prompt, and start the DISKPART console. List all of your disks by typing LIST DISK, then select the proper disk with SELECT DISK # (where # is the SD card). You can then type CLEAN to clear the partition table on the card, effectively blanking it. MAKE SURE YOU SELECTED THE PROPER DISK BEFORE RUNNING THE CLEAN COMMAND!
To create a primary partition to reuse the space on the card, type CREATE PARTITION PRIMARY. This will then reallocate the previously "cleaned" space.
To format, type FORMAT FS=FAT32 QUICK, and finally, to reassign a drive letter, type ASSIGN.
If you're unable to determine the proper disk, remove the SD card, run DISKPART and LIST DISK, and then re-run it with the SD card inserted. The SD card is just the disk that has been added.
Note that the above commands are not case sensitive; I used caps to match the convention DISKPART displays.
FDISK / CFDISK (Linux/Mac)
In a terminal, start fdisk /dev/sdx where /dev/sdx is your SD card device (may depend on the Linux distro you're using, see below). You can then delete all existing partitions on the device by typing d, and then adding a single new partition & format it. You an also just type n to create a new partition table, and start laying everything out.
cfdisk is also another viable tool, which is basically fdisk with a greatly improved user interface. In both cases, once the drive is formatted, you will lastly need to mount it.
If you're unable to determine the proper device, remove the SD card, run fdisk -l, and then re-run it with the SD card inserted. The SD card is just the device that has been added.
04-13-2016 08:48 AM
I found a solution that worked easily for me.
My SanDisk 2Gb was offering me only 34Mb and I didn't even formatted it.
So I tried formatting and nothing worked.
I found this How-to Geek answer and followed the steps and I recovered the whole 2Gb.
Formatted it as NTFS afterward because it is more up to date and you won't get the "Need to format" message anymore.
At least, I didn't get it after format.
So here is the address :
I made myself a copy of the steps in case it happen again and
I added the lines
"Redo the List disk again and you will see an asterix aside (on the left) of the disk 1 and that tells you chose the right disk."
"Whatever commands you execute after this point will only make changes to the selected disk; now would be a good time to double check you’ve selected the right disk just to be extra safe."
Because it would be unfortunate to wipe out all my C:\ drive instead of the SD Card.
Make sure you see the little asterix aside the SD Card Disk number ID and then do a Clean command.
After, you format and there you go.
11-12-2017 08:29 AM
Hey Guys! I had an 8GB that only shows 1.8GB. I had used it in a garmin GPS to update the GPS unit. Well it went in with 8GB and came out with only 1.8GB. The garmin can only use 2GB, so it partitioned the chip for 2GB. But I found this really brilliant video that shows how to re-partition the chip and it worked like a champ. here is the youtube web site.
good luck, but be careful what you are working with, cuz you could mess up your main computer drive if you're not.