. Using the wrong file for a different variant (like the CPH1801) could permanently destroy the motherboard.
The tech plugs the phone into a PC. It doesn't show up as a "Phone"; it shows up as "MediaTek USB Port." This is the phone's "limbo" state.
This refers to the Android version (Nougat). In the world of "dead fixes," you often need the exact firmware version the phone was running before it died to successfully handshake with the hardware.