diff --git a/ethereum/contracts/Shutdown.sol b/ethereum/contracts/Shutdown.sol
new file mode 100644
index 000000000..ca4a31f53
--- /dev/null
+++ b/ethereum/contracts/Shutdown.sol
@@ -0,0 +1,31 @@
+// contracts/Shutdown.sol
+// SPDX-License-Identifier: Apache 2
+
+pragma solidity ^0.8.0;
+pragma experimental ABIEncoderV2;
+
+import "./Governance.sol";
+
+import "@openzeppelin/contracts/proxy/ERC1967/ERC1967Upgrade.sol";
+
+/**
+ * @title  Shutdown
+ * @notice This contract implements a stripped-down version of the Wormhole core
+ *         messaging protocol that is a drop-in replacement for Wormhole's
+ *         implementation contract, effectively disabling all non-governance
+ *         functionality.
+ *         In particular, outgoing messages are disabled, but the contract
+ *         remains upgradeable through governance.
+ */
+contract Shutdown is Governance  {
+
+    function initialize() public {
+        address implementation = ERC1967Upgrade._getImplementation();
+        setInitialized(implementation);
+
+        // this function needs to be exposed for an upgrade to pass
+        // NOTE: leave this function empty! It specifically does not have an
+        // 'initializer' modifier, to allow this contract to be upgraded to
+        // multiple times.
+    }
+}
diff --git a/ethereum/contracts/bridge/BridgeShutdown.sol b/ethereum/contracts/bridge/BridgeShutdown.sol
new file mode 100644
index 000000000..11c5c5d93
--- /dev/null
+++ b/ethereum/contracts/bridge/BridgeShutdown.sol
@@ -0,0 +1,36 @@
+// contracts/BridgeShutdown.sol
+// SPDX-License-Identifier: Apache 2
+
+pragma solidity ^0.8.0;
+
+import "./BridgeGovernance.sol";
+
+import "@openzeppelin/contracts/security/ReentrancyGuard.sol";
+import "@openzeppelin/contracts/proxy/ERC1967/ERC1967Upgrade.sol";
+
+/**
+ * @title  BridgeShutdown
+ * @notice This contract implements a stripped-down version of the token bridge
+ *         asset transfer protocol that is a drop-in replacement for the Bridge
+ *         implementation contract, effectively disabling all non-governance
+ *         functionality.
+ *         In particular, sending and receiving assets is disabled, but the
+ *         contract remains upgradeable through governance.
+ * @dev    Technically the ReentrancyGuard is not used in this contract,
+ *         but it adds a storage variable, so as a matter of principle, we
+ *         inherit that here too in order keep the storage layout identical to
+ *         the actual implementation contract (which does use the reentrancy
+ *         guard).
+ */
+contract BridgeShutdown is BridgeGovernance, ReentrancyGuard {
+
+    function initialize() public {
+        address implementation = ERC1967Upgrade._getImplementation();
+        setInitialized(implementation);
+
+        // this function needs to be exposed for an upgrade to pass
+        // NOTE: leave this function empty! It specifically does not have an
+        // 'initializer' modifier, to allow this contract to be upgraded to
+        // multiple times.
+    }
+}
diff --git a/ethereum/contracts/nft/NFTBridge.sol b/ethereum/contracts/nft/NFTBridge.sol
index 98742bff0..42e60e22d 100644
--- a/ethereum/contracts/nft/NFTBridge.sol
+++ b/ethereum/contracts/nft/NFTBridge.sol
@@ -1,4 +1,4 @@
-// contracts/Bridge.sol
+// contracts/NFTBridge.sol
 // SPDX-License-Identifier: Apache 2
 
 pragma solidity ^0.8.0;
@@ -241,7 +241,7 @@ contract NFTBridge is NFTBridgeGovernance {
 
         transfer.tokenID = encoded.toUint256(index);
         index += 32;
-        
+
         // Ignore length due to malformatted payload
         index += 1;
         transfer.uri = string(encoded.slice(index, encoded.length - index - 34));
diff --git a/ethereum/contracts/nft/NFTBridgeGetters.sol b/ethereum/contracts/nft/NFTBridgeGetters.sol
index 666fb0584..9c510a829 100644
--- a/ethereum/contracts/nft/NFTBridgeGetters.sol
+++ b/ethereum/contracts/nft/NFTBridgeGetters.sol
@@ -1,4 +1,4 @@
-// contracts/Getters.sol
+// contracts/NFTBridgeGetters.sol
 // SPDX-License-Identifier: Apache 2
 
 pragma solidity ^0.8.0;
diff --git a/ethereum/contracts/nft/NFTBridgeGovernance.sol b/ethereum/contracts/nft/NFTBridgeGovernance.sol
index 3cc4f9545..0213088d0 100644
--- a/ethereum/contracts/nft/NFTBridgeGovernance.sol
+++ b/ethereum/contracts/nft/NFTBridgeGovernance.sol
@@ -1,4 +1,4 @@
-// contracts/Bridge.sol
+// contracts/NFTBridgeGovernance.sol
 // SPDX-License-Identifier: Apache 2
 
 pragma solidity ^0.8.0;
diff --git a/ethereum/contracts/nft/NFTBridgeImplementation.sol b/ethereum/contracts/nft/NFTBridgeImplementation.sol
index b00c3eb6e..499850843 100644
--- a/ethereum/contracts/nft/NFTBridgeImplementation.sol
+++ b/ethereum/contracts/nft/NFTBridgeImplementation.sol
@@ -1,4 +1,4 @@
-// contracts/Implementation.sol
+// contracts/NFTBridgeImplementation.sol
 // SPDX-License-Identifier: Apache 2
 
 pragma solidity ^0.8.0;
diff --git a/ethereum/contracts/nft/NFTBridgeSetters.sol b/ethereum/contracts/nft/NFTBridgeSetters.sol
index b5048dbb2..518729e73 100644
--- a/ethereum/contracts/nft/NFTBridgeSetters.sol
+++ b/ethereum/contracts/nft/NFTBridgeSetters.sol
@@ -1,4 +1,4 @@
-// contracts/Setters.sol
+// contracts/NFTBridgeSetters.sol
 // SPDX-License-Identifier: Apache 2
 
 pragma solidity ^0.8.0;
diff --git a/ethereum/contracts/nft/NFTBridgeSetup.sol b/ethereum/contracts/nft/NFTBridgeSetup.sol
index c1c7aeaf5..f313b2ea5 100644
--- a/ethereum/contracts/nft/NFTBridgeSetup.sol
+++ b/ethereum/contracts/nft/NFTBridgeSetup.sol
@@ -1,4 +1,4 @@
-// contracts/BridgeSetup.sol
+// contracts/NFTBridgeSetup.sol
 // SPDX-License-Identifier: Apache 2
 
 pragma solidity ^0.8.0;
diff --git a/ethereum/contracts/nft/NFTBridgeShutdown.sol b/ethereum/contracts/nft/NFTBridgeShutdown.sol
new file mode 100644
index 000000000..a797b9f61
--- /dev/null
+++ b/ethereum/contracts/nft/NFTBridgeShutdown.sol
@@ -0,0 +1,30 @@
+// contracts/NFTBridgeShutdown.sol
+// SPDX-License-Identifier: Apache 2
+
+pragma solidity ^0.8.0;
+
+import "./NFTBridgeGovernance.sol";
+
+import "@openzeppelin/contracts/proxy/ERC1967/ERC1967Upgrade.sol";
+
+/**
+ * @title  BridgeShutdown
+ * @notice This contract implements a stripped-down version of the NFT bridge
+ *         asset transfer protocol that is a drop-in replacement for the
+ *         NFTBridge implementation contract, effectively disabling all
+ *         non-governance functionality.
+ *         In particular, sending and receiving assets is disabled, but the
+ *         contract remains upgradeable through governance.
+ */
+contract NFTBridgeShutdown is NFTBridgeGovernance {
+
+    function initialize() public {
+        address implementation = ERC1967Upgrade._getImplementation();
+        setInitialized(implementation);
+
+        // this function needs to be exposed for an upgrade to pass
+        // NOTE: leave this function empty! It specifically does not have an
+        // 'initializer' modifier, to allow this contract to be upgraded to
+        // multiple times.
+    }
+}
diff --git a/ethereum/scripts/deploy_core_bridge_shutdown.js b/ethereum/scripts/deploy_core_bridge_shutdown.js
new file mode 100644
index 000000000..b2d53f948
--- /dev/null
+++ b/ethereum/scripts/deploy_core_bridge_shutdown.js
@@ -0,0 +1,11 @@
+const Shutdown = artifacts.require("Shutdown");
+module.exports = async function(callback) {
+  try {
+    const contract = (await Shutdown.new());
+    console.log('tx: ' + contract.transactionHash);
+    console.log('Shutdown address: ' + contract.address);
+    callback();
+  } catch (e) {
+    callback(e);
+  }
+};
diff --git a/ethereum/scripts/deploy_nft_bridge_shutdown.js b/ethereum/scripts/deploy_nft_bridge_shutdown.js
new file mode 100644
index 000000000..2d67c8d7c
--- /dev/null
+++ b/ethereum/scripts/deploy_nft_bridge_shutdown.js
@@ -0,0 +1,11 @@
+const Shutdown = artifacts.require("NFTBridgeShutdown");
+module.exports = async function(callback) {
+  try {
+    const contract = (await Shutdown.new());
+    console.log('tx: ' + contract.transactionHash);
+    console.log('NFTBridgeShutdown address: ' + contract.address);
+    callback();
+  } catch (e) {
+    callback(e);
+  }
+};
diff --git a/ethereum/scripts/deploy_token_bridge_shutdown.js b/ethereum/scripts/deploy_token_bridge_shutdown.js
new file mode 100644
index 000000000..3ab532a20
--- /dev/null
+++ b/ethereum/scripts/deploy_token_bridge_shutdown.js
@@ -0,0 +1,11 @@
+const Shutdown = artifacts.require("BridgeShutdown");
+module.exports = async function(callback) {
+  try {
+    const contract = (await Shutdown.new());
+    console.log('tx: ' + contract.transactionHash);
+    console.log('Bridge address: ' + contract.address);
+    callback();
+  } catch (e) {
+    callback(e);
+  }
+};
diff --git a/ethereum/simulate_upgrade b/ethereum/simulate_upgrade
index 8299d1fcc..b340aa98e 100755
--- a/ethereum/simulate_upgrade
+++ b/ethereum/simulate_upgrade
@@ -15,7 +15,7 @@ function usage() {
 cat <<EOF >&2
 Usage:
 
-  $(basename "$0") [-h] [-m s] [-c s] [-x] [-k] [-d] [-a s] [-l s] -- Simulate an upgrade on a fork of mainnet, and check for any errors.
+  $(basename "$0") [-h] [-m s] [-c s] [-x] [-k] [-d] [-a s] [-l s] [-s] -- Simulate an upgrade on a fork of mainnet, and check for any errors.
 
   where:
     -h  show this help text
@@ -24,8 +24,9 @@ Usage:
     -x  run anvil
     -d  don't compile contract first
     -k  keep anvil alive
-    -l  file to loge to (by default creates a new tmp file)
+    -l  file to log to (by default creates a new tmp file)
     -a  new code address (by default it builds the most recent contract in the repository)
+    -s  shutdown
 EOF
 exit 1
 }
@@ -40,8 +41,9 @@ chain_name=""
 run_anvil=false
 skip_compile=false
 keepalive_anvil=false
+shutdown=false
 anvil_out=$(mktemp)
-while getopts ':hm:c:a:xkdl:' option; do
+while getopts ':hm:c:a:xkdl:s' option; do
   case "$option" in
     h) usage
        ;;
@@ -60,6 +62,8 @@ while getopts ':hm:c:a:xkdl:' option; do
     k) keepalive_anvil=true
        run_anvil=true
        ;;
+    s) shutdown=true
+       ;;
     :) printf "missing argument for -%s\n" "$OPTARG" >&2
        usage
        ;;
@@ -111,15 +115,27 @@ SCRIPT=""
 case "$module" in
     bridge|core)
         MODULE=Core
-        SCRIPT="scripts/deploy_core_bridge.js"
+        if [[ $shutdown = true ]]; then
+            SCRIPT="scripts/deploy_core_bridge_shutdown.js"
+        else
+            SCRIPT="scripts/deploy_core_bridge.js"
+        fi
         ;;
     token_bridge)
         MODULE=TokenBridge
-        SCRIPT="scripts/deploy_token_bridge.js"
+        if [[ $shutdown = true ]]; then
+            SCRIPT="scripts/deploy_token_bridge_shutdown.js"
+        else
+            SCRIPT="scripts/deploy_token_bridge.js"
+        fi
         ;;
     nft_bridge)
         MODULE=NFTBridge
-        SCRIPT="scripts/deploy_nft_bridge.js"
+        if [[ $shutdown = true ]]; then
+            SCRIPT="scripts/deploy_nft_bridge_shutdown.js"
+        else
+            SCRIPT="scripts/deploy_nft_bridge.js"
+        fi
         ;;
     *) echo "unknown module $module" >&2
        usage
diff --git a/ethereum/simulate_upgrades b/ethereum/simulate_upgrades
index b4db38191..7e1d6e2c9 100755
--- a/ethereum/simulate_upgrades
+++ b/ethereum/simulate_upgrades
@@ -28,17 +28,23 @@ ANVIL_PID=$!
 # Sleep for 10 seconds here to give some time for the fork to complete.
 sleep 10
 
-echo "========================= Updating core contract #1 ============================"
+echo "========================= Updating core contract ============================"
 ./simulate_upgrade -m bridge -c $chain -d
-echo "========================= Updating core contract #2 ============================"
+echo "========================= Shutting down core contract ======================="
+./simulate_upgrade -m bridge -c $chain -d -s
+echo "========================= Re-enabling core contract ========================="
 ./simulate_upgrade -m bridge -c $chain -d
 
-echo "===================== Updating token bridge contract #1 ========================"
+echo "===================== Updating token bridge contract ========================"
 ./simulate_upgrade -m token_bridge -c $chain -d
-echo "===================== Updating token bridge contract #2 ========================"
+echo "===================== Shutting down token bridge contract ==================="
+./simulate_upgrade -m token_bridge -c $chain -d -s
+echo "===================== Re-enabling token bridge contract ====================="
 ./simulate_upgrade -m token_bridge -c $chain -d
 
-echo "====================== Updating NFT bridge contract #1 ========================="
+echo "====================== Updating NFT bridge contract ========================="
 ./simulate_upgrade -m nft_bridge -c $chain -d
-echo "====================== Updating NFT bridge contract #2 ========================="
+echo "====================== Shutting down NFT bridge contract ===================="
+./simulate_upgrade -m nft_bridge -c $chain -d -s
+echo "====================== Re-enabling NFT bridge contract ======================"
 ./simulate_upgrade -m nft_bridge -c $chain -d