If you're looking to get data back without any hardware hacking, I highly recommend Disk Drill. It's recovered files from microSD cards most of my devices couldn't even detect.
A couple years ago I was trying to extract and interpret information from a NAND flash chip. I was able to get a dump of the bytes, and identified the pages and their spare areas. But I never was able to figure out the logical ordering of the pages. What all the bits in the spare areas meant, which pages were bad, etc. So I never was able to reconstruct a logical view of the disk.
I tried reading datasheets, but they didn't seem to have the full picture. Had I know about this document then I might have had a chance at figuring it out.
The datasheets just tell you how to read the physical structure. How the logical structure maps to that is via the FTL, which is going to be proprietary and need to be reverse-engineered almost 100% of the time.
