Yep. As soon as you find the sector number of the start of your data, you can use "losetup --offset xxxxx" to use it like a regular disk again. I think there are even SCSI commands you could send to permanently shift the start of the disk. Or you could just dd all your data back to where it ought to be.
I read a bit more and it seems some models has encryption mode (by default using an empty string for a password it seems.) There exist at least two projects to get data from those MyBooks so I'll try those if the simple version doesn't work.
