: For many Samsung models, a "Patch Cert" or "Patch Network" command must be run after the IMEI repair to restore cellular signal .
His client, an elderly woman named Martha, was distraught. The phone held the only photos of her grandson’s graduation, and now it was a glorified paperweight, showing "Invalid IMEI" and refusing to connect to any network.
Paid tools patch the NVRAM permanently, surviving future OTA updates. Free tools often break after a firmware upgrade.