I just uploaded all the
.MYI files from a MySQL 4 server to a server running MySQL 5.
At first I took the advice I've seen on this site, and didn't copy the
.MYI files. I ran a phpmyadmin repair and it said the
.MYI files were missing. It didn't re-create them. So I went ahead and copied them over and ran the repair again and everything looked perfect. I was able to browse the tables and see that all the data was intact. And phpmyadmin gave green check marks next to every table.
I haven't had a chance to test the site yet to verify that it's all working, but I'll write back and let you all know.