Chosen Solution
Should I replace the WiFi IC? Or the antenna? I heard changing of WiFi IC would disable WiFi function? it that real?
Wi-Fi IC (Also known as Wi-Fi chipset) requires micro-soldering to replace the chip and the NAND would also need to be reprogrammed to have the matching MAC address to the Wi-Fi IC. Weak signal is more likely caused by damaged iPhone housing / antenna cables or connectors.
