We have four Sena 20s EVO that all worked fine before updating the firmware to v2.2.3.  Yes, firmware update was completed successfully on all four devices.   

We tried factory reset of devices, installed latest device mgr. and firmware.  Android and iPhone Sena app.  Audio is dead on four 20s EVO on four different helmets.  We rotated the testing, etc.  Nothing has restored the audio after firmware update. . . 

What is the solution?  We have used Sena 20s EVO devices for the last 10+ years.  Thank you