Its easy to downgrade dash, but not the kernel. And font/audio exploit works with new dash (live 2: 5***) if you just get a copy of old dash (live 1: 49**) and overwrite it on the new one, then you have the old dash. (I know its serval ways to downgrade). When done, just do the font/audio exploit like oldays.
PBL does't work because the kernel blocks it, with PBL you dont have to sign xbe, and other good things like IGR. But you still able to play games from hdd or BU and other things like run xbmc etc.
Correct me if I am wrong and sorry for my bad english.