I had an HDD with bad sectors. Tried to recover some info with Disk Drill (which I successfully did) but not all because of the bad sectors. So I tried to make a duplicate of a big folder which was affected by the bad sectors using this tutorial. It created the DMG file but then, when I tried to mount it, it says "no mountable file systems". So far I tried the terminal way of hdiutil and some related codes without success. I can't repair or anything from de Disk Utility. I mounted it on Disk Drill and it searches for Recoverable information but it's in the 50% without showing any recoverable files. The DMG is like 366 Gb large, so the info must be there. No very familiar with all this topics but if it matters, the partition map scheme says "No partition map".
This is driving me crazy.
Is there software to fix a DMG or recover files from them?