CR2 metadata/usability restoration

[ewg]

I've been recently wondering to what extend is it feasible to reconstruct a broken-metadata raw photo file (.CR2)...

If I'm pretty sure that a file's actual image data is intact and coherent (jpeg thumnail&preview+raw/tiff streams) but only the metadata section (~2KB at the very begining) of the file is significantly damaged (overwritten), beyond recogntion to any standard raw editing software (DPP,ACR,ExifTool...) - is the raw data practically gone or there are some tools/tricks to help?

Here is an example of a file recovered after being deleted and accidentally overwritten with a short xml text (~2KB): http://www.sendspace.com/file/2ita37 (beware of ads!, look for: "Click here to start download from sendspace")

I've already extracted the jpeg preview with a hex editor but could I do more?

[Phil Harvey]

This is something that ExifTool can't help with, but you could presumably take a good original image and swap in the parts that are damaged/missing from this file (like using the frog for the missing bits of the dino-DNA in Jurassic Park).  Of course, the color balance etc. may be incorrect, but at least you have something to play around with in Lightroom.

Without looking at this in detail, it should be do-able but to automate this may require knowledge about the offsets where a specific camera models stores the data in a CR2 image.  So it may be a lot of work to generalize something like this.

- Phil

[ewg]

I've already trided the "DNA" methode without success. Thus not knowing the specific offsets I consider it much more delete-able than do-able. Thank you!