If you are saying what I think you are, this is a known issue with 4.XX CFW and not multiMAN. Having 2 USB's drives with games on them, will only allow you to play games from one USB drive. The other drive should allow you to see it the contents, and do some other things that are limited, but not load games without them black screening. There is currently no fix and this like i said is an issue with 4.XX+ CFW and not mM. Both Team Rebug and Dean have tried many combinations to no avail. Basically the only solution is to use one USB drive (with games on it) at a time. So this means after unplugging dev_usb000 and rebooting you should be able to play the games on dev_usb071. Also using a HUB and changing usb ports will not resolve this issue either, as I said it's a 4.00+ CFW issue.