Aircard MSL code for factory reset

Hi,  I've got a Boost branded, but unlocked, Aircard that *was* working fine.  Then one day it did some sort of reset and locked itself to Sprint.    I did a 3rd party unlock which appears to work but now it still wants to be activated with Sprint.    I'm trying to go through the various reset options but I'm stuck on the MSL code for a factory reset.

Any way of determining what that is?  Most internet instructions are for devices with a keypad....

Firmware NTG9X15A_01.08.02.00

Thanks,