diff --git a/modules/home/core/default.nix b/modules/home/core/default.nix
index d4524af..d52a532 100644
--- a/modules/home/core/default.nix
+++ b/modules/home/core/default.nix
@@ -241,8 +241,21 @@ in
             set -l last_argv $argv
             echo \"$argv[1]\" Command Not Found
           '';
-          update-hm = "home-manager switch -L --flake nixconf &| nom";
-          update-sys = "sudo nixos-rebuild switch --log-format internal-json -v --flake nixconf &| nom --json";
+          update-sys = ''
+            argparse -i 'f/flake=' -- $argv
+            set -f mode switch
+            if set -q argv[1]
+              set -f mode $argv[1]
+            end
+
+            set -f flake nixconf
+            if set -q _flag_f
+              set -f flake $_flag_f
+            end
+
+            sudo echo -n # Make sure sudo has already prompted for password.
+            sudo nixos-rebuild $mode --log-format internal-json -v --flake $flake &| nom --json
+          '';
         };
         interactiveShellInit = ''
           abbr --position anywhere -a !! -f last_cmd