here's a link to the website, that neo-ag(NAT member) mentioned in that other link, I showed on previous reply.

http://greenfieldag.com/?page_id=1065

Scroll down to

 "Ez-Guide 500 v5.12(current) "

download that to a thumb drive.

Note: My 500 unit was an Ag Leader "branded"  unit and I actually got my software download off of Ag Leader Knowledge Base website.

2nd note: I did watch this 10 year old video, a couple of times, and he mentioned the downloads must be in "files" (not a folder) to be able for the 500 unit to accept them. (very important)

https://www.youtube.com/watch?v=er6gZC3bxyo

Remember this video, is 10 years old, thus it doesn't show 5.12 version, back then