Just search for a free md5 checker, they are simple to use. You do realize that DVD/BluRay playback doesn't work quite right in JB mode? When I put DVDs in mine it recognizes them as data discs and not video discs. I've never tried to use the video library or anything in JB mode, but you did say you were having trouble loading game managers, so I would download the second version of 3.41, check the MD5, and upload that to see if it solves your issue.
Originally Posted by Motorhead
No, that is the current version of 3.50 direct from Sony, DO NOT update to that. You need to look around for someone who has the older version.