The head unit sees your phone, but won't connect, or drops audio constantly. The reality: The AVH-P3450DVD uses Bluetooth 1.1 or 2.0 (HSP/HFP profiles). Modern iPhones and Androids use Bluetooth 5.0+ and often drop legacy support for A2DP 1.0. The fix: No firmware can upgrade a 2009 Bluetooth chip to 2026 standards. Use an AUX cable or an FM transmitter instead.
They sell a CD that contains a .jpeg image and a small .bin file that writes that image to the display memory. They call this a "Firmware Update v3.0." Pioneer Avh P3450dvd Firmware Update
The process for this model is manual and requires precision to avoid "bricking" the unit. Pioneer India How to update firmware on pioneer touchscreen 20-Dec-2022 — The head unit sees your phone, but won't