I am using UART sensors that do not allow the RPI to finish the boot when the serial console and the bluetooth are on. I did disable them using the dtoverlay=pi3-disable-bt in /boot/config.txt and deleted the serial console parameters from the /boot/cmdline.txt, but the problem is that they are still on during the boot and they only get disabled after, which does not allow my pi to boot when I have my UART sensors plugged in. Does anyone know how this could be fixed?

EDIT: It might be that my pi does not boot because the sensors connected send garbage to the board, which cause my u-boot to stop at hit any key to stop u-boot, hence I am thinking that setting that key to something pre-defined instead of "any key" could solve my problem. However, I don't know how to do that, could anyone help?

Thank you

  • sensors connected send garbage .... the "garbage" could still contain the predefined key press – jsotola May 22 '18 at 17:33

I managed to solve the problem. I modified the u-boot variable setenv stdin nulldev, setting a pre-defined u-boot stop key or setting bootdelay = 0 did not solve my problem.

Hope this helps.


You can solve this by setting the bootdelay of u-boot to -2 using the u-boot console:

setenv bootdelay=-2

Another solution is adding these lines of code to include/configs/rpi.h:

#define CONFIG_AUTOBOOT_PROMPT "\nRPi booting... Stop with ENTER\n"

See also here.

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