JpegDigger will examine multiple RAW files for the JPEG header and process corrupt RAW files. This is the last freeware version. JpegDigger is now Shareware.
Currently supported RAW file types include .NEF, .CR2, .CRW, .ORF, .ARW, .SRW, .PEF, .DNG, .3FR, .RAF and .RW2 RAW camera images.
One problem we had with testing is that we lacked a corrupt RAW file to test with, so we can't speak to how effective it is. We were able to load a sample.NEF for the fun of testing. Drag-and-drop is also supported. You can see our tests in the screenshots below.
There are a couple of known limitations to the effectiveness, per the author. One is that your chances of recovery are better if JpegDigger shows you a preview. The other is the possibility of your RAW software being much older than JpegDigger, so it might appear corrupt when it's not.
Anything having to do with recovering all or part of a corrupt file is a hit and miss proposition. However, if you've got a corrupt RAW file, JpegDigger is worth a try.