If you are recording and run out of space on the card, when you try to extract the dng files you'll get the following error:
Error: This ain't a lv_rec RAW file
You need to replace the file footer information to get this back.
Here's what I did, and I'm sure there are easier ways, but this is free.
Step 1:
Download the freeware Hex editor from here:
http://mh-nexus.de/en/downloads.php?product=HxDStep 2: Open the .raw file in the hex editor. Scroll all the way to the bottom.
You have 2 choices at this point:
Option 1 - Record another file with the same settings on the card, and retrieve the footer information in the hex editor. It should be the last 12 lines of the file. The downside to doing it this way is it'll only extract the same number of DNG files that the secondary file has listed; i.e. if your 2nd file is 200 megs or so, if you copy that file's footer information to the (assuming) larger troubled file, you'll only be able to pull out the first 50 or so dng files.
So I suggest you do #2:
Option 2 - Copy and paste this into your file footer:
52 41 57 4D 80 07 38 04 00 5F 37 00 F4 21 00 00 01 00 00 00 A8 5D 00 00 18 02 98 19 18 02 98 19 01 00 00 00 00 20 15 0B 26 05 00 00 20 08 00 00 38 0E 00 00 50 34 49 00 0E 00 00 00 0C 08 00 00 98 3A 00 00 00 00 00 00 00 00 00 00 88 07 00 00 08 05 00 00 1E 00 00 00 92 00 00 00 26 05 00 00 1A 08 00 00 00 00 00 00 00 00 00 00 00 01 01 02 01 00 00 00 42 1A 00 00 10 27 00 00 85 FD FF FF 10 27 00 00 3D FC FF FF 10 27 00 00 41 EF FF FF 10 27 00 00 AC 30 00 00 10 27 00 00 EC 07 00 00 10 27 00 00 74 FC FF FF 10 27 00 00 72 08 00 00 10 27 00 00 24 16 00 00 10 27 00 00 82 03 00 00
Save the file, and start unpacking your dng's!
This will work for file sizes up to 32gb.
**Of note - say your "bad" file was smaller than 32GB - let's say it was 11GB - by using this footer it will try to unpack 8692 DNG files. Since I'm not smart enough to read hex, I just estimate where the good dng files should be and delete everything after it.
Here's a screen shot of the pasted in footer: