For the second time in a year, I had a windows system crash with a large capacity (500GB) FAT32 partitioned drive mounted and amidst the crash, it somehow obliterated both the primary and backup boot sectors making the drive unmountable and unrecoverable with standard fsck tools.
The first time this happened, I researched through hundreds of threads and could not find a way to rebuild the partition map and I resigned to proceeding with raw data recovery which took several days (USB to USB).
With the info I had gathered last time and a ****-ton of trial and error today, I was abe to come up with a routine to rebuild the partition map while keeping all of data in tact.
sudo apt-get install testdisk
>Create a new log file
[Accept Defaults and Write]
>(Q)uit until exited
Give Microsoft the bird and disco/reconnect drive.