diff --git a/script/Benchmark.s.sol b/script/Benchmark.s.sol
index a25a2ba..5e62a31 100644
--- a/script/Benchmark.s.sol
+++ b/script/Benchmark.s.sol
@@ -60,7 +60,9 @@ contract Benchmark is Script, OneInchContracts {
     v5AggregationRouter.swap(v5AggregationExecutor, v5Desc, v5Permit, v5Data);
 
     // Optimized router v5 swap call
-    (bool v5Ok,) = payable(v5Rtr).call(abi.encode(DAI, 100_000, v5Desc.minReturnAmount, v5Data, 0));
+    (bool v5Ok,) = payable(v5Rtr).call(
+      abi.encodePacked(DAI, uint96(100_000), uint96(v5Desc.minReturnAmount), uint256(0), v5Data)
+    );
 
     if (!v5Ok) revert OptimizedV5RouterFailed();
 
@@ -78,7 +80,9 @@ contract Benchmark is Script, OneInchContracts {
     v4AggregationRouter.swap(v4AggregationExecutor, v4Desc, v4Data);
 
     // Optimized v4 swap call
-    (bool v4Ok,) = payable(v4Rtr).call(abi.encode(DAI, 100_000, v4Desc.minReturnAmount, v4Data, 0));
+    (bool v4Ok,) = payable(v4Rtr).call(
+      abi.encodePacked(DAI, uint96(100_000), uint96(v4Desc.minReturnAmount), uint256(0), v4Data)
+    );
     if (!v4Ok) revert OptimizedV4RouterFailed();
   }
 }
diff --git a/src/V4Router.sol b/src/V4Router.sol
index d36ab33..9061eec 100644
--- a/src/V4Router.sol
+++ b/src/V4Router.sol
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-pragma solidity >=0.8.0;
+pragma solidity ^0.8.0;
 
 import {IERC20} from "openzeppelin-contracts/contracts/token/ERC20/IERC20.sol";
 
@@ -22,8 +22,12 @@ contract V4Router is AggregationV4BaseRouter {
 
   // Flags match specific constant masks. There is no documentation on these.
   fallback() external payable {
-    (address dstToken, uint256 amount, uint256 minReturnAmount, bytes memory data, uint256 flags) =
-      abi.decode(msg.data, (address, uint256, uint256, bytes, uint256));
+    address dstToken = address(bytes20(msg.data[0:20]));
+    uint256 amount = uint256(uint96(bytes12(msg.data[20:32])));
+    uint256 minReturnAmount = uint256(uint96(bytes12(msg.data[32:44])));
+    uint256 flags = uint256(uint8(bytes1(msg.data[44:45])));
+    bytes memory data = bytes(msg.data[45:msg.data.length]);
+
     IERC20(TOKEN).transferFrom(msg.sender, address(this), amount);
     AGGREGATION_ROUTER.swap(
       AGGREGATION_EXECUTOR,
diff --git a/src/V5Router.sol b/src/V5Router.sol
index 4c10a01..d8c8b70 100644
--- a/src/V5Router.sol
+++ b/src/V5Router.sol
@@ -22,8 +22,12 @@ contract V5Router is AggregationV5BaseRouter {
 
   // Flags match specific constant masks. There is no documentation on these.
   fallback() external payable {
-    (address dstToken, uint256 amount, uint256 minReturnAmount, bytes memory data, uint256 flags) =
-      abi.decode(msg.data, (address, uint256, uint256, bytes, uint256));
+    address dstToken = address(bytes20(msg.data[0:20]));
+    uint256 amount = uint256(uint96(bytes12(msg.data[20:32])));
+    uint256 minReturnAmount = uint256(uint96(bytes12(msg.data[32:44])));
+    uint256 flags = uint256(uint8(bytes1(msg.data[44:45])));
+    bytes memory data = bytes(msg.data[45:msg.data.length]);
+
     IERC20(TOKEN).transferFrom(msg.sender, address(this), amount);
     AGGREGATION_ROUTER.swap(
       AGGREGATION_EXECUTOR,
diff --git a/test/V4Router.t.sol b/test/V4Router.t.sol
index 3435036..04a17ac 100644
--- a/test/V4Router.t.sol
+++ b/test/V4Router.t.sol
@@ -100,7 +100,9 @@ contract Fallback is V4RouterTest {
     assertEq(startingUNIBalance, 0, "Starting balance is incorrect");
 
     // Optimized router call
-    (bool ok,) = payable(routerAddr).call(abi.encode(UNI, 100_000, desc.minReturnAmount, data, 0));
+    (bool ok,) = payable(routerAddr).call(
+      abi.encodePacked(UNI, uint96(100_000), uint96(desc.minReturnAmount), uint8(0), data)
+    );
 
     assertTrue(ok, "Swap failed");
 
@@ -130,8 +132,9 @@ contract Fallback is V4RouterTest {
     vm.startPrank(swapSenderAddress);
     IERC20(USDC).approve(routerAddr, 10_000_000);
     uint256 startingBalance = IERC20(USDC).balanceOf(swapSenderAddress);
-    (bool ok,) =
-      payable(routerAddr).call(abi.encode(UNI, 10_000_000, desc.minReturnAmount, data, 0));
+    (bool ok,) = payable(routerAddr).call(
+      abi.encodePacked(UNI, uint96(10_000_000), uint96(desc.minReturnAmount), uint8(0), data)
+    );
     uint256 endingBalance = IERC20(USDC).balanceOf(swapSenderAddress);
 
     assertTrue(!ok, "Swap succeeded");
@@ -142,8 +145,9 @@ contract Fallback is V4RouterTest {
     (IV4AggregationRouter.SwapDescription memory desc, bytes memory data) = helper_apiParams();
     IERC20(USDC).approve(routerAddr, 250_000);
     uint256 startingBalance = IERC20(USDC).balanceOf(swapSenderAddress);
-    (bool ok,) =
-      payable(routerAddr).call(abi.encode(address(0), 250_000, desc.minReturnAmount, data, 0));
+    (bool ok,) = payable(routerAddr).call(
+      abi.encodePacked(address(0), uint96(250_000), uint96(desc.minReturnAmount), uint8(0), data)
+    );
     uint256 endingBalance = IERC20(USDC).balanceOf(swapSenderAddress);
 
     assertTrue(!ok, "Swap succeeded");
diff --git a/test/V5Router.t.sol b/test/V5Router.t.sol
index afe6d15..9600db4 100644
--- a/test/V5Router.t.sol
+++ b/test/V5Router.t.sol
@@ -106,7 +106,9 @@ contract Fallback is V5RouterTest {
     assertEq(startingUNIBalance, 0, "Starting balance is not 0");
 
     // Optimized router call
-    (bool ok,) = payable(routerAddr).call(abi.encode(UNI, 100_000, desc.minReturnAmount, data, 0));
+    (bool ok,) = payable(routerAddr).call(
+      abi.encodePacked(UNI, uint96(100_000), uint96(desc.minReturnAmount), uint8(0), data)
+    );
 
     assertTrue(ok, "Swap failed");
 
@@ -136,8 +138,9 @@ contract Fallback is V5RouterTest {
     vm.startPrank(swapSenderAddress);
     IERC20(USDC).approve(routerAddr, 10_000_000);
     uint256 startingBalance = IERC20(USDC).balanceOf(swapSenderAddress);
-    (bool ok,) =
-      payable(routerAddr).call(abi.encode(UNI, 10_000_000, desc.minReturnAmount, data, 0));
+    (bool ok,) = payable(routerAddr).call(
+      abi.encodePacked(UNI, uint96(10_000_000), uint96(desc.minReturnAmount), uint8(0), data)
+    );
     uint256 endingBalance = IERC20(USDC).balanceOf(swapSenderAddress);
 
     assertTrue(!ok, "Swap succeeded");
@@ -148,8 +151,11 @@ contract Fallback is V5RouterTest {
     (IV5AggregationRouter.SwapDescription memory desc,, bytes memory data) = helper_apiParams();
     IERC20(USDC).approve(routerAddr, 250_000);
     uint256 startingBalance = IERC20(USDC).balanceOf(swapSenderAddress);
-    (bool ok,) =
-      payable(routerAddr).call(abi.encode(address(0), 250_000, desc.minReturnAmount, data, 0));
+    (bool ok,) = payable(routerAddr).call(
+      abi.encodePacked(
+        address(0), uint96(250_000), uint96(desc.minReturnAmount), uint8(0), bytes(data)
+      )
+    );
     uint256 endingBalance = IERC20(USDC).balanceOf(swapSenderAddress);
     assertTrue(!ok, "Swap succeeded");
     assertEq(startingBalance, endingBalance, "Funds were held by the router contract");