If you are performing these repairs, keep the following in mind:
Stock ROM users. Cost: Free.
If your phone boots, dial *#*#3646633#*#* to enter Engineer Mode (MTK). Go to Connectivity -> CDS Information -> Radio Information. But usually, if IMEI is 0, you can't write here directly. You need the tools below. redmi 9 imei repair unlock tool
Before using any , understand this: