6.How to use the coaxial function of JM21?................................................................38
7. What can be done if I forget my password? How to enter recovery mode? 38
Firmware upgrade, factory data reset and technical support ........................................ 39
1.How to upgrade firmware?........................................................................................... 39
2.Force to reboot................................................................................................................. 40
3.Factory data reset.............................................................................................................41
4.Technical support ............................................................................................................. 41