List of things you might need to do to develop OBD Linux on Raspberry Pi with Buildroot

host

$ sudo apt-get install build-essential 
$ sudo apt-get install ncurses-dev
$ sudo apt-get install flex
$ sudo apt-get install bison
$ sudo apt-get install python
$ sudo apt-get install unzip

menuconfig

make raspberrypi3_defconfig

Change to the default setting for Raspberry Pi 3. By the way,

make list-defconfigs

You can see the full list at. What is raspberrypi3_qt5we?

After that, refer to here

• Enable cache at build time
• Allow IP to be obtained from DHCP server
• Enable SSH
• Allow SSH login with host name

Make ELM327 available

make linux-menuconfig

After that

Device Drivers ->
    USB support -> 
        USB Serial Converter support
            USB_SERIAL_PL2303 (USB Prolific 2303 Single Port Serial Driver)

Enable and include the driver in the image.

Then do whatever you want

After setting, try python-obd with python, try Qt5 from menuconfig, boil or bake freely!