You can’t change the radio modem on the device, as you asked.
The issues with Verizon are two:
- Some bands are not supported. But most are. In general, the BraX3 will have good connectivity on Verizon network, if not for issue 2
- Verizon is blocking service to any device that is not approved by them. They shared that they can not approve the BraX3 since it is missing some bands. They are able to validate a device model by the device IMEI. If you have a Verizon compatible device, you can write its IMEI to the BraX3 device so that Verizon won’t block you.