In the Android world, this is called a . Without a valid NVRAM file, your MYA-L22 is essentially a very nice paperweight that cannot make calls or connect to mobile data.
If you previously backed up your device using SP Flash Tool or a custom recovery, you can simply flash your original NVRAM/NVDATA image back to the device to restore your unique IMEI. 2. Using Stock Firmware mya-l22 nvram file