The device is usually put into a specific "Flash Mode" or "Diag Mode" where the tool can communicate directly with the Unisoc processor.

Wait for “Pass” or “Write Success” in green.

is the safest route to reload the stock operating system and restore the original IMEI without risking a "bricked" (permanently dead) device. Quick Diagnostics Before seeking repair, verify your current status: Check via Dialer to see if numbers appear. Check via Settings About Device Basic Reset

You are not alone. The Realme C30s (model number RMX3644) is a budget powerhouse, but like many MediaTek-powered devices, it is prone to IMEI corruption after firmware updates, rooting attempts, or flashing stock ROMs.