I tried to made a binary upgrade using freebsd-upgrade from freebsd 11 to the latest 12.2 on i386 machine with old 586 processor. The system failed to boot with illegal instruction error (see attached picture). Upgrading from sources on freebsd 11 produces buildable kernel but unworkable system. Cross compiling i386 system on amd64 produces similar error.
Created attachment 220974 [details]
Screenshot of the crash
Just in case, it's the loader that crashes.
Not sure. I am able to load previous kernel with the same loader