Going backwards: Restoring to previous versions of Firmware, in other words downgrading. When traveling back in time and reverting to a previous version of SymNet Designer, there are a few gotchas to be aware of:

First… Turn off All Amplifiers! You’re upgrading (or in this case, downgrading) an entire audio system! Murphy’s Law always applies – anything can happen and will happen. Do not turn on the amps until you are sure all software changes/reconfigurations are finished and successful. Then, it is suggested that you turn the amps down and ease them up. An ounce of precaution is worth a pound of cure. Also, in later versions of SymNet Designer (version 3.5 or higher), the volume will ramp up after a Site file is downloaded according to a time setting in the Preferences dialog box located in the File pull-down menu. Set this for a long ramp up period. If there is distortion, feedback or unintended routing in the system, it will ramp up slowly and give you time to react. Consider yourself warned.

Next, you need to downgrade the system in reverse order. So, you must start with the highest numbered device address in a ring and work backwards in decending address order. If you change the Master unit to a previous version first (i.e. the first unit in a SymNet Ring), you will not be able to address the Slave units through the SymLink bus. If this happens, you have 2 options:
Change the Master unit back to the “more recent” version and then begin the firmware downgrade process again starting with the last unit.

Disconnect the SymLink connections from all units. Change the DIP switches on the back of the slave units to make them a master unit and change all their addresses to ID #1. Then, connect to the front panel of each unit individually and perform the upgrade (downgrade). Finally, reconfigure the DIP switches to their original settings, re-patch the SymLink bus and re-power the system.

Make sure you have an older version of the SymNet Site File! This is important, as when you double click on a SymNet file, Windows will launch the Site File with the last version of SymNet Designer software installed, not the older version, and your Site File will be loaded into it. If Auto Save is turned on (Go to the File pull-down menu and select Preferences to see the Auto Save Enable setting) in the newer version and it executes a Save, then you have essentially upgraded your Site File. Now it will not open in the earlier version. It is best to have a copy that is saved in the previous version that has not been opened in the newer version.

For more information on upgrading SymNet systems, see the ReadMe file that accompanies every software release.