I FOUND A BUG IN 4.21CFW OR IN MULTIMAN 4.08.01
 

i was having a big trouble trying to load games, having black screen after clicked on disc icon in xmb...so after many trys i discovered that i was having black screen because i have 2 HDs, so a disconected 1 and all the games run fine, but with the 2 conectec give me black screen.

You should report the bug at >tortuga-cove< that way @Rogero can look into it.

I thought I read someone over there with the same issue but can't say if it's resolved or not.

This was established a couple of days ago at least so I'm positive it's something that's being dealt with.

I read that the backups only works when you put the external USB in the port most nearest to the BD-Drive, in the other the games just give black screen.
Regards