You will need to search for a "JioFi M2S Universal Firmware" file. These are usually hosted on developer forums like XDA-Developers or specialized GSM sites.
Disclaimer: Firmware flashing is done at your own risk. Modifying your device's official software voids its warranty. Unlock Jiofi M2s
You will need a Windows PC to run the required firmware flashing and port detection tools. You will need to search for a "JioFi
Put the battery back in, but do not turn the device on normally. Unlock Jiofi M2s