Raspberry Pi 4 and Latest Raspbian Bookworm OS.

I want to have Pi 4 communicate over serial connection using GPIO14 (BCM) and GPIO15 (BCM) or UART TX and UART RX.

I have followed the same setups that I have done for my previous Pis (2 and 3) as follows to enable serial communication.

  • executed sudo raspi-config to enable serial interface to YES.
  • installed wiringpi.
  • set GPIO14 and GPIO15 to ALT0.
  • Added enable_uart=1 and also disabled bluetooth dtoverylay=disable-bt in /boot/config.txt.
  • Disabled ttyAMA0 by sudo systemctl mask [email protected]
  • Reboot Pi.

These steps works and worked on my previous versions of pi but not on Pi 4.

No data is transmitted, but after much testing I noticed that whenever I re-enable bluetooth by commenting out dtoverlay=disable-bt in /boot/config.txt Pi 4 transmits outgoing data but DOES NOT READ the incoming serial data.

There is obviously some differences in Pi 4 and the previous versons of Pis. I can't seem to find any solutions that work so far.

Any hints or clues?

  • You have posted no diagnostics and are using unusual (and unnecessary) commands. If you just tried the standard commands it should work. Frankly I fail to understand WHY so many people want to disable Bluetooth. The Pi4 has 5 usable UART.
    – Milliways
    Nov 11, 2023 at 0:26

1 Answer 1


In the latest version of Rasperry Pi OS from late 2023, with the Bookworm kernel, config.txt should be in /boot/firmware, ie /boot/firmware/config.txt

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