dd'ed to wrong disk (same old story)

[aleritty]

Hello!

I'm a Linux user from years but never tried an actual recovery of lost data.

I have an external USB3 Toshiba HDD, 1TB, was ext4 formatted and quite full (one big partition).

Yesterday night I got wrong and instead of writing (with dd) an iso image to an USB key I started writing to the HD. I stopped dd after 1GB was wrote (wow, USB3 is so fast! dammit!)

Now, i really need to recover from the untouched 999GB, but with me I don't have an equal capacity disk to clone to.

I'm trying with testdisk but it can find only one linux type partition (with the correct disklabel), a FAT partition (created by the ISO?) and if I do a deeper scan a LOT of linux partition with vary start-end sectors, every partition is empty.

Maybe is possible to reconstruct the partition after that 1G?

Thank you in advance for your help.

[harddrivespecialist]

Best thing is to do the same thing to a drive with some random data and practice to get your data back.

[aleritty]

Ok,
stated that I made a dd image of the disk so the data is (hopefully) "safe", maybe can you give me some advice?

I know that inside an expert forum this may sound like clueless, but for example making another etx4 partition without formatting maybe can help?

Or what is the "best practice" in your opinion in this scenario?

Maybe I don't have another drive to play with, and if I search the forum I find a lot of more desperate situations "solved", but nothing similar

[harddrivespecialist]

Do NOT write anything to that drive.
Find another drive and make an image, otherwise you can delete all data and move on.