{
  pkgs,
  lib,
  namespace,
  ...
}:
{
  boot = {
    #   loader.raspberry-pi = {
    #     firmwarePackage = kernelBundle.raspberrypifw;
    #     variant = "4";
    #   };
    #   kernelPackages = kernelBundle.linuxPackages_rpi4;
    # kernelPackages = pkgs.${namespace}.linuxPackages_cachyos-lto;
    kernelPackages = pkgs.${namespace}.linuxPackages_rpi4-lts;
    supportedFilesystems = lib.mkForce [ ];
  };

  specialisation = {
    "linux-latest".configuration = {
      boot = {
        kernelPackages = lib.mkOverride 90 pkgs.unstable.linuxPackages_latest;
      };
    };
  };

  ${namespace}.hardware.raspberry-pi.config = {
    all = {
      # [all] conditional filter, https://www.raspberrypi.com/documentation/computers/config_txt.html#conditional-filters

      base-dt-params = {
        i2c_arm = {
          enable = true;
          value = "on";
        };
        i2c = {
          enable = true;
          value = "on";
        };
        spi = {
          enable = true;
          value = "on";
        };
      };

      options = {
        # https://www.raspberrypi.com/documentation/computers/config_txt.html#enable_uart
        # in conjunction with `console=serial0,115200` in kernel command line (`cmdline.txt`)
        # creates a serial console, accessible using GPIOs 14 and 15 (pins
        #  8 and 10 on the 40-pin header)
        enable_uart = {
          enable = true;
          value = true;
        };
        # https://www.raspberrypi.com/documentation/computers/config_txt.html#uart_2ndstage
        # enable debug logging to the UART, also automatically enables
        # UART logging in `start.elf`
        uart_2ndstage = {
          enable = true;
          value = true;
        };
      };

      # Base DTB parameters
      # https://github.com/raspberrypi/linux/blob/a1d3defcca200077e1e382fe049ca613d16efd2b/arch/arm/boot/dts/overlays/README#L132
      base-dt-params = {

      };

    };
  };
}