I HAVE FOUND THE TRUE 4000NEX IMAGE FILE. I'm going to provide it below in a link and a step by step on how to get this piece of crap radio system back in order.
Install Win32DiskImager (https://sourceforge.net/projects/win32diskimager/) I had difficulty with this version, it kept crashing, so I installed version 0.9.5 and ran it in administrator and it worked like a charm.
Write this image file onto your 4-8gb SDHC SD card using that program.
AVH-4000NEX Image File: https://avichacking.slack.com/files/UE0G0SC84/FEE5UPR46/4000nex.rar
If that one doesn'