Get data back from unpartitionned Hard Drive

I recently got access to a few hard drives deemed broken. Needless to say that after a quick check, what happened is that they were formatted... but not properly. I managed to get the data back using fdisk, giving it back and resetting the hard drive properly.

I tried testdisk and other utilities but what did the trick was fdisk.

When listing /dev/sdb on testdisk I was seeing 3Tb of space and only 2.7Tb are in a partition called /dev/sdb1. That means that there was another partition there.

Running fdisk /dev/sdb showed only one partition.

But using fdisk, you can add a partition that has a bit of a bigger size than the unpartitionned space (fdisk -> p). I am still trying to figure out why this worked and didn't wipe all the data but I was surprised when a /dev/sdb2 showed up that was NOT empty after mounting.

If you know why that worked let me know, I am still trying to collect my thoughts.

This makes me wonder, data recovery is an absolute fun thing to do. I love it.

PS: No I did not check if there were Bitcoins.