Some Blackberry OS version may have performance issue with PrivateGSM and sometimes a firmware downgrade is required.
This is the step-to-step procedure
- Go to Blackberry Download site and select the right Mobile Operator.
- Follow the download procedure and download the firmware file
- Install the file on a Windows machine (MacOSX and Linux OS is not supported by RIM)
- Open Blackberry Desktop Software and connect the device
- Once the device is detected, open the Device menu and select "Update"
- A popup windows is shown with a message like "No update available for Blackberry Device Software"
- Select "Show other versions" in the bottom-left of the popup.
- Select the right version number and click install
The downgrade procedure will starts.