Rpi zero 2w in Prusa 3D printer; aka: data received via UART (over GPIO) disturbs the boot process

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And it works…

Quicky more hacky way is below.
Basically just change activation string from any key,
to semi random string disables parsing of garbage received via UART.

  nixpkgs.overlays = [
    (self: super: {
      ubootRaspberryPi3_64bit = super.ubootRaspberryPi3_64bit.overrideAttrs (oldAttrs: {
        extraConfig = ''
          CONFIG_BOOTDELAY=-2
          CONFIG_SILENT_CONSOLE=y
          CONFIG_SYS_DEVICE_NULLDEV=y
          CONFIG_SILENT_CONSOLE_UPDATE_ON_SET=y
          CONFIG_SILENT_U_BOOT_ONLY=y
          CONFIG_AUTOBOOT_KEYED=y
          CONFIG_AUTOBOOT_PROMPT="NO UART\0"
          CONFIG_AUTOBOOT_DELAY_STR="dfg\0"
          CONFIG_AUTOBOOT_STOP_STR="1234\0"
        '';
      });
...

However, I still need to edit extlinux configuration manually and remove
MENU and TIMEOUT lines. Because I just want to go to last generation only.

TIMEOUT -10 line, which is generated by boot.loader.timeout = 0;
doesn’t seems to work and we are stuck in menu.

Maybe I need just add some hacks to:

which removes MENU and TIMEOUT from generated file.

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