HELP on Network Baseband issue -Xperia M2 Dual - Selected USA Band accidently

Please help to find the solution on radio base band issue once selected USA Band
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Xperia M2 Dual, D2302., Lollipop 5.1.1 - ( Firmware 18.6.A.0.182)
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This is how it accidentally happened: USA Band selected.
Dial *#*#4636#*#* > Testing menu > Phone information > Select Radio Band > USA Band (No other option in the list).
Lost network, SIM network stopped working now.
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All below action already performed:
- Bootloader is unlocked
- Successfully connects to ADB and fastboot
- Applied below Fastboot commands:
Fastboot erase modemst1 > Returns with failed (Command not allowed)
Fastboot erase modemst2 > Returns with Failed (Command not allowed)
Fastboot erase cache > Ok

- Also connected to Sony Emma > flash mode – can't see option anything to flash modem.img /radio.img
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How to get to the solution to reset back now?
Please comment help!
Thank you!

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