How do I use my microsd card again after formatting in unknown format accidentally and is no longer recognized?

Question

I was trying to setup an Ubuntu Remix boot-up drive on my 4GB microsd card and accidentally formatted the card in some unknown format.

1. Is there a way to determine what format I actually did format it into?
2. Is there a way to re-format the card so I can use it again? Right now Ubuntu and Debian won't even recognize the card at all ... I don't see it anywhere.

Answer 1

Try GPartEd first. It should show the device, as long as the card is plugged in. If not, the long way around it is:

1. Take care at each step below. If you choose the wrong device in step 5, you will destroy all data on that device upon repartition/format
2. Open up a shell (Terminal) window.
3. Execute sudo fdisk -l (will ask for your acct password) and take note of the output, seeing which Disk entries are listed (like /dev/sda, /dev/sdb etc).
4. Plug in your card and re-run sudo fdisk -l to see the list of devices. There should be a new one in the list. Let's say it's /dev/SD for example, but substitute accordingly.
5. Execute sudo fdisk /dev/SD
6. Hit p to see how many partitions are on the device, then d with the appropriate number to delete all of them.
7. Hit n and create a new primary partition. If you now hit p you should see it in the list. Hit w to write the new partition table to disk.
8. Format the new partition with mkfs.ext2 /dev/SD1
9. It should now show up.

Answer 2

When you say that they won't recognize the card at all, do you mean that they won't mount it, or that they don't even appear in /dev/?

I'd get a partitioning tool (GPartEd is my favorite on Linux) and take a look at the card. Does it appear in the device list?