diff --git a/pkgs/vivado/vivado.nix b/pkgs/vivado/vivado.nix
index 321a347..5d250ac 100644
--- a/pkgs/vivado/vivado.nix
+++ b/pkgs/vivado/vivado.nix
@@ -5,14 +5,19 @@
   fetchurl,
   lib,
   runtimeShell,
-  macAddress ? lib.warn ''
-    In order for licensing to work, you need to manually provide your licensed machine's MAC address.
-    This can be done in two ways:
-      a) Set an env var `XILINX_NIC_ID=xx:xx:xx:xx:xx:xx`
-      b) Override the package `(vivado.override { macAddress = "xx:xx:xx:xx:xx:xx"; })`
-    If both are configured, the environment variable takes precedence.
-    Run `vlm` to see the current licensing status of your installation.
-  '' "aa:aa:aa:aa:aa:aa",
+  enableMacSpoofing ? false,
+  macAddress ?
+    if enableMacSpoofing then
+      lib.warn ''
+        In order for licensing to work, you need to manually provide your licensed machine's MAC address.
+        This can be done in two ways:
+          a) Set an env var `XILINX_NIC_ID=xx:xx:xx:xx:xx:xx`
+          b) Override the package `(vivado.override { macAddress = "xx:xx:xx:xx:xx:xx"; })`
+        If both are configured, the environment variable takes precedence.
+        Run `vlm` to see the current licensing status of your installation.
+      '' "aa:aa:aa:aa:aa:aa"
+    else
+      null,
   licensePath ? null,
   extraProfile ? "",
   extraPkgs ? pkgs: [ ],
@@ -311,21 +316,22 @@ buildFHSEnv (finalAttrs: rec {
       ln -s ${unwrapped}/share/desktop-directories $out/share/desktop-directories
     '';
 
-  runScript = "";
-  unshareNet = true;
-  extraBwrapArgs = [ "--cap-add CAP_NET_ADMIN" ];
-
+  unshareNet = enableMacSpoofing;
+  extraBwrapArgs = lib.optional enableMacSpoofing "--cap-add CAP_NET_ADMIN";
   profile =
     let
       XILINXD_LICENSE_FILE = lib.optionalString (!isNull licensePath) ''
         : ''${XILINXD_LICENSE_FILE:=${licensePath}}
         export XILINXD_LICENSE_FILE
       '';
+      XILINX_NIC_ID = lib.optionalString enableMacSpoofing ''
+        : ''${XILINX_NIC_ID:=${macAddress}}
+        ip link add eth0 type dummy
+        ip link set dev eth0 address $XILINX_NIC_ID
+      '';
     in
     ''
-      : ''${XILINX_NIC_ID:=${macAddress}}
-      ip link add eth0 type dummy
-      ip link set dev eth0 address $XILINX_NIC_ID
+      ${XILINX_NIC_ID}
       ${XILINXD_LICENSE_FILE}
       export LC_NUMERIC="en_US.UTF-8"
       export GDK_BACKEND=x11
@@ -335,10 +341,7 @@ buildFHSEnv (finalAttrs: rec {
       source ${unwrapped}/opt/Xilinx/${version}/Vivado/settings64.sh
     ''
     + extraProfile;
-
-  # wanted by $unwrapped/opt/Xilinx/${version}/data/emulation/sctlm/lib/libhls_emsyn.so:
-  # "libLLVM-3.1.so"
-  # "libhls_hwsyn.so"
+  runScript = "";
 
   inherit (unwrapped) meta;
 })