diff --git a/artiq/gateware/targets/efc.py b/artiq/gateware/targets/efc.py
index 637844dc0..92cd2e771 100644
--- a/artiq/gateware/targets/efc.py
+++ b/artiq/gateware/targets/efc.py
@@ -167,6 +167,7 @@ def main():
         description="ARTIQ device binary builder for EEM FMC Carrier systems")
     builder_args(parser)
     parser.set_defaults(output_dir="artiq_efc")
+    parser.add_argument("-V", "--variant", default="shuttler")
     parser.add_argument("--gateware-identifier-str", default=None,
                         help="Override ROM identifier")
     args = parser.parse_args()
diff --git a/flake.nix b/flake.nix
index 5ea21b24f..2acbdb65e 100644
--- a/flake.nix
+++ b/flake.nix
@@ -358,10 +358,9 @@
           target = "kc705";
           variant = "nist_clock";
         };
-        artiq-board-efc = makeArtiqBoardPackage {
+        artiq-board-efc-shuttler = makeArtiqBoardPackage {
           target = "efc";
           variant = "shuttler";
-          buildCommand = "python -m artiq.gateware.targets.efc";
         };
         inherit sphinxcontrib-wavedrom latex-artiq-manual;
         artiq-manual-html = pkgs.stdenvNoCC.mkDerivation rec {
@@ -462,7 +461,7 @@
       };
 
       hydraJobs = {
-        inherit (packages.x86_64-linux) artiq artiq-board-kc705-nist_clock artiq-board-efc openocd-bscanspi;
+        inherit (packages.x86_64-linux) artiq artiq-board-kc705-nist_clock artiq-board-efc-shuttler openocd-bscanspi;
         gateware-sim = pkgs.stdenvNoCC.mkDerivation {
           name = "gateware-sim";
           buildInputs = [