You may find ZTE MF275U router locked to a particular network. Factory unlock code of ZTE MF275U is also available. Now, unlocking of this router is also possible, if it is asking for NCK after changing the SIM card.
Once the ZTE MF275U is unlocked, you can use all supported bands SIM cards of any carrier. Unlocking is one-time work, but the freedom to choose any network provider SIM card.
This router is currently available in the USA by US Cellular carrier. You may find in another country too.
How long we need to wait for an unlock code of ZTE?
The approximate delivery time for a ZTE unlock code is 1 to 24 hrs.
The average response time for a ZTE unlock code is 2 hrs (based on last 100 orders).
How to Unlock ZTE MF275U?
1. Switch Off the ZTE MF275U.
2. Change the default SIM card with any another carrier.
3. Connect to PC with USB cable.
4. It will automatically open the default web page of the ZTE MF275U, if not then open My Computer >> Virtual CD-ROM and install in your PC.
5. Login to the device through web page with admin.
6. It should redirect you to the unlocking page and will ask you for NCK.
7. Enter here correct factory unlock code and click OK.
8. The device may be rebooted to show the network.
9. Now you can start using your ZTE MF275U with any carrier SIM card.
Note: If above procedure does not work, then let me know via comments, I will fix it.
Note I: Factory unlock code of ZTE MF275U is not free, you need to pay. Correct SIMlock code will be emailed. While paying, mention the IMEI in the transaction.