nixos/console: set colors using kernel parameters

This commit changes the console colors implementation
to use the kernel parameters instead of relying on terminal
escape sequences. This means the palette is applied by the
kernel itself with no custom code running in the initrd
and works for all virtual terminals (not only tty0).

nixos/modules/config/console.nix

@@ -6,10 +6,7 @@ with lib;
 let
   cfg = config.console;
 
-  makeColor = n: value: "COLOR_${toString n}=${value}";
-  makeColorCS =
-    let positions = [ "0" "1" "2" "3" "4" "5" "6" "7" "8" "9" "A" "B" "C" "D" "E" "F" ];
-    in n: value: "\\033]P${elemAt positions (n - 1)}${value}";
+  makeColor = i: concatMapStringsSep "," (x: "0x" + substring (2*i) 2 x);
 
   isUnicode = hasSuffix "UTF-8" (toUpper config.i18n.defaultLocale);
 
@@ -25,7 +22,6 @@ let
   vconsoleConf = pkgs.writeText "vconsole.conf" ''
     KEYMAP=${cfg.keyMap}
     FONT=${cfg.font}
-    ${concatImapStringsSep "\n" makeColor cfg.colors}
   '';
 
   consoleEnv = pkgs.buildEnv {
@@ -160,10 +156,6 @@ in
           ${optionalString cfg.earlySetup ''
             setfont -C /dev/console $extraUtils/share/consolefonts/font.psf
           ''}
-
-          ${concatImapStringsSep "\n" (n: color: ''
-            printf "${makeColorCS n color}" >> /dev/console
-          '') cfg.colors}
         '';
 
         systemd.services.systemd-vconsole-setup =
@@ -173,6 +165,14 @@ in
           };
       }
 
+      (mkIf (cfg.colors != []) {
+        boot.kernelParams = [
+          "vt.default_red=${makeColor 0 cfg.colors}"
+          "vt.default_grn=${makeColor 1 cfg.colors}"
+          "vt.default_blu=${makeColor 2 cfg.colors}"
+        ];
+      })
+
       (mkIf cfg.earlySetup {
         boot.initrd.extraUtilsCommands = ''
           mkdir -p $out/share/consolefonts