When Dingleberry was released, Research in Motion pulled all it’s old Playbook OSes in an attempt to prevent rooting.
Luckily, some folks here on OSBB are borderline-OCD when it comes to backing up BlackBerry stuff. This was one of those times when that paid off.
From this page, you can obtain a download link for every OS that was available for the BlackBerry Playbook as of October 2010, and every OS that has been released since then. Additional OSes will be added as they come available.
These OSes contain every bar that would be downloaded by BlackBerry Desktop Manager in a zip folder. For information on installing these files, check out http://opensourcebb.com/2011/12/downgrade-playbook-os-local-copy/. Hopefully before too long BNXTreme will get us a tool that can be used to downgrade to whatever OS you want (they gave us a taste of it with Dingleberry 3.0).
IF YOU HAVE A PLAYBOOK OS NOT LISTED HERE, WE’D LOVE TO HAVE IT!