Do not mix a European firmware (EU) with an Indian device (IN) – this will hard brick the modem.
Firmware is a type of software that is embedded in a hardware device, such as a smartphone, to control its functions. It acts as an intermediary between the device's hardware and operating system, enabling the device to perform various tasks. Firmware is usually stored in non-volatile memory, which means it remains intact even when the device is powered off. Firmware REDMI 9C