After updating my PS3 firmware from 2.01 to v2.1 everything looks OK on the Game OS side, but when I switch to the "OtherOS" I just get a blank screen and no drive activity or anything.
I use a different bootloader to load Yellow Dog 5.0.1 (the one from the install DVD) and it still works, but the one I've been using for Fedora doesn't. The one from this rar archive here
still works for Fedora 7.
Also, there may be a change that prevents ps3rsx from working ... see this post
Before updating to the new FW 2.1 you may want to go ahead and change your /etc/X11/xorg.conf file back to using fbdev instead of ps3 if you're using the ps3rsx module and X driver. Also you may need the bootloader linked