Code:
snmpset -v2c -c public 192.168.100.1 1.3.6.1.4.1.4413.2.99.1.1.1.2.1.2.1 s password
snmpget -v2c -c public 192.168.100.1 1.3.6.1.2.1.1.1.0
First one will put it in Factory Mode, the second will verify to you it is in Factory Mode (you can find these and other commands in OneClickFlash)