I have 5220 and 5224 handsets connecting to a cloud based hosted VoIP PBX. The phones boot fine and generally work fine however once a week or two phones will generate the error: Assert@121 #0r-13 rtos_mutex.cpp
The handset then requires a reboot to get it going again. It happens randomly to all handsets at any moment. The virtual PBX host requires us to use firmware version 4.00.00.13 for the phones so they are all at that version level.
Can anyone offer some information on what this error means and how I can fix it? Is it a firmware bug?
