dacbert, radiobert: allow /dev/mem access for gpio

hosts/dacbert/default.nix

@@ -31,10 +31,13 @@
       };
     };
 
+    kernelPackages = pkgs.linuxPackages_latest;
     kernelParams = lib.mkForce [
       "snd_bcm2835.enable_headphones=1"
       # don't let sd-image-aarch64.nix setup serial console as it breaks bluetooth.
       "console=tty0"
+      # allow GPIO access
+      "iomem=relaxed" "strict-devmem=0"
     ];
 
     tmpOnTmpfs = true;

hosts/radiobert/default.nix

@@ -42,6 +42,11 @@
     };
 
     kernelPackages = pkgs.linuxPackages_latest;
+    kernelParams = lib.mkForce [
+      "console=tty0"
+      # allow GPIO access
+      "iomem=relaxed" "strict-devmem=0"
+    ];
     # No ZFS on latest kernel:
     supportedFilesystems = lib.mkForce [ "vfat" "ext4" ];