11-26-2012 03:51 PM
"Old OS" is a bit of a problem...no one else can possibly know what version you are wanting...only you can know that. But, the simplest way is to, on a PC (you cannot do this on MAC):
1) Uninstall, from your PC, any BB OS packages
2) Make sure you have the BB Desktop Software already installed
3) Download and install, to your PC, the BB OS package you desire:
4) If that OS package is from a carrier other than the carrier for which your BB was originally manufactured, then delete, on your PC, all copies of VENDOR.XML...there will be at least one, and perhaps 2, and they will be located in or similarly to (it changes based on your Windows version) these folders:
5) Launch the Desktop Software and connect your BB...the software should offer you the OS package you installed to your PC. If, during the process, your BB presents a "507" error, simply unplug the USB cord from the BB and re-insert it...don't do anything else...this should allow the install to continue.
Don't forget to backup.
If you are on MAC, you are limited to only your carriers sanctioned OS packages...but can still use any levels that they currently sanction. See this procedure:
Good luck and let us know!