diff --git a/contracts/utils/Arrays.sol b/contracts/utils/Arrays.sol
index 0783614cd3e..3cfa44f5ffa 100644
--- a/contracts/utils/Arrays.sol
+++ b/contracts/utils/Arrays.sol
@@ -31,7 +31,7 @@ library Arrays {
 
             // Note that mid will always be strictly less than high (i.e. it will be a valid array index)
             // because Math.average rounds down (it does integer division with truncation).
-            if (array[mid] > element) {
+            if (unsafeAccess(array, mid) > element) {
                 high = mid;
             } else {
                 low = mid + 1;
@@ -39,10 +39,21 @@ library Arrays {
         }
 
         // At this point `low` is the exclusive upper bound. We will return the inclusive upper bound.
-        if (low > 0 && array[low - 1] == element) {
+        if (low > 0 && unsafeAccess(array, low - 1) == element) {
             return low - 1;
         } else {
             return low;
         }
     }
+
+    /**
+     * @dev Access an array in an "unsafe" way. Skips solidity "index-out-of-range" check.
+     * @notice WARNING: only use if you are certain pos is lower then the array length.
+     */
+    function unsafeAccess(uint256[] storage arr, uint256 pos) internal view returns (uint256 result) {
+        assembly {
+            mstore(0, arr.slot)
+            result := sload(add(keccak256(0, 0x20), pos))
+        }
+    }
 }
diff --git a/contracts/utils/Checkpoints.sol b/contracts/utils/Checkpoints.sol
index c0f6c82b3c3..495be349c3b 100644
--- a/contracts/utils/Checkpoints.sol
+++ b/contracts/utils/Checkpoints.sol
@@ -23,7 +23,7 @@ library Checkpoints {
 
     function latest(Checkpoint224[] storage self) internal view returns (uint224) {
         uint256 pos = self.length;
-        return pos == 0 ? 0 : self[pos - 1]._value;
+        return pos == 0 ? 0 : _unsafeAccess(self, pos - 1)._value;
     }
 
     function push(
@@ -35,14 +35,14 @@ library Checkpoints {
 
         if (pos > 0) {
             // Use of memory is important here.
-            Checkpoint224 memory last = self[pos - 1];
+            Checkpoint224 memory last = _unsafeAccess(self, pos - 1);
 
             // Checkpoints keys must be increassing.
             require(last._key <= key, "Checkpoint: invalid key");
 
             // Update or push new checkpoint
             if (last._key == key) {
-                self[pos - 1]._value = value;
+                _unsafeAccess(self, pos - 1)._value = value;
             } else {
                 self.push(Checkpoint224({_key: key, _value: value}));
             }
@@ -56,20 +56,20 @@ library Checkpoints {
     function lowerLookup(Checkpoint224[] storage self, uint32 key) internal view returns (uint224) {
         uint256 length = self.length;
         uint256 pos = _lowerDichotomicLookup(self, key, 0, length);
-        return pos == length ? 0 : self[pos]._value;
+        return pos == length ? 0 : _unsafeAccess(self, pos)._value;
     }
 
     function upperLookup(Checkpoint224[] storage self, uint32 key) internal view returns (uint224) {
         uint256 length = self.length;
         uint256 pos = _upperDichotomicLookup(self, key, 0, length);
-        return pos == 0 ? 0 : self[pos - 1]._value;
+        return pos == 0 ? 0 : _unsafeAccess(self, pos - 1)._value;
     }
 
     function upperLookupRecent(Checkpoint224[] storage self, uint32 key) internal view returns (uint224) {
         uint256 length = self.length;
         uint256 offset = 1;
 
-        while (offset <= length && self[length - offset]._key > key) {
+        while (offset <= length && _unsafeAccess(self, length - offset)._key > key) {
             offset <<= 1;
         }
 
@@ -77,7 +77,7 @@ library Checkpoints {
         uint256 high = length - (offset >> 1);
         uint256 pos = _upperDichotomicLookup(self, key, low, high);
 
-        return pos == 0 ? 0 : self[pos - 1]._value;
+        return pos == 0 ? 0 : _unsafeAccess(self, pos - 1)._value;
     }
 
     function _upperDichotomicLookup(
@@ -88,7 +88,7 @@ library Checkpoints {
     ) private view returns (uint256) {
         while (low < high) {
             uint256 mid = Math.average(low, high);
-            if (self[mid]._key > key) {
+            if (_unsafeAccess(self, mid)._key > key) {
                 high = mid;
             } else {
                 low = mid + 1;
@@ -105,7 +105,7 @@ library Checkpoints {
     ) private view returns (uint256) {
         while (low < high) {
             uint256 mid = Math.average(low, high);
-            if (self[mid]._key < key) {
+            if (_unsafeAccess(self, mid)._key < key) {
                 low = mid + 1;
             } else {
                 high = mid;
@@ -114,6 +114,13 @@ library Checkpoints {
         return high;
     }
 
+    function _unsafeAccess(Checkpoint224[] storage self, uint256 pos) private view returns (Checkpoint224 storage result) {
+        assembly {
+            mstore(0, self.slot)
+            result.slot := add(keccak256(0, 0x20), pos)
+        }
+    }
+
     struct Checkpoint160 {
         uint96 _key;
         uint160 _value;
@@ -121,7 +128,7 @@ library Checkpoints {
 
     function latest(Checkpoint160[] storage self) internal view returns (uint160) {
         uint256 pos = self.length;
-        return pos == 0 ? 0 : self[pos - 1]._value;
+        return pos == 0 ? 0 : _unsafeAccess(self, pos - 1)._value;
     }
 
     function push(
@@ -133,14 +140,14 @@ library Checkpoints {
 
         if (pos > 0) {
             // Use of memory is important here.
-            Checkpoint160 memory last = self[pos - 1];
+            Checkpoint160 memory last = _unsafeAccess(self, pos - 1);
 
             // Checkpoints keys must be increassing.
             require(last._key <= key, "Checkpoint: invalid key");
 
             // Update or push new checkpoint
             if (last._key == key) {
-                self[pos - 1]._value = value;
+                _unsafeAccess(self, pos - 1)._value = value;
             } else {
                 self.push(Checkpoint160({_key: key, _value: value}));
             }
@@ -154,20 +161,20 @@ library Checkpoints {
     function lowerLookup(Checkpoint160[] storage self, uint96 key) internal view returns (uint160) {
         uint256 length = self.length;
         uint256 pos = _lowerDichotomicLookup(self, key, 0, length);
-        return pos == length ? 0 : self[pos]._value;
+        return pos == length ? 0 : _unsafeAccess(self, pos)._value;
     }
 
     function upperLookup(Checkpoint160[] storage self, uint96 key) internal view returns (uint160) {
         uint256 length = self.length;
         uint256 pos = _upperDichotomicLookup(self, key, 0, length);
-        return pos == 0 ? 0 : self[pos - 1]._value;
+        return pos == 0 ? 0 : _unsafeAccess(self, pos - 1)._value;
     }
 
     function upperLookupRecent(Checkpoint160[] storage self, uint96 key) internal view returns (uint224) {
         uint256 length = self.length;
         uint256 offset = 1;
 
-        while (offset <= length && self[length - offset]._key > key) {
+        while (offset <= length && _unsafeAccess(self, length - offset)._key > key) {
             offset <<= 1;
         }
 
@@ -175,7 +182,7 @@ library Checkpoints {
         uint256 high = length - (offset >> 1);
         uint256 pos = _upperDichotomicLookup(self, key, low, high);
 
-        return pos == 0 ? 0 : self[pos - 1]._value;
+        return pos == 0 ? 0 : _unsafeAccess(self, pos - 1)._value;
     }
 
     function _upperDichotomicLookup(
@@ -186,7 +193,7 @@ library Checkpoints {
     ) private view returns (uint256) {
         while (low < high) {
             uint256 mid = Math.average(low, high);
-            if (self[mid]._key > key) {
+            if (_unsafeAccess(self, mid)._key > key) {
                 high = mid;
             } else {
                 low = mid + 1;
@@ -203,7 +210,7 @@ library Checkpoints {
     ) private view returns (uint256) {
         while (low < high) {
             uint256 mid = Math.average(low, high);
-            if (self[mid]._key < key) {
+            if (_unsafeAccess(self, mid)._key < key) {
                 low = mid + 1;
             } else {
                 high = mid;
@@ -212,6 +219,13 @@ library Checkpoints {
         return high;
     }
 
+    function _unsafeAccess(Checkpoint160[] storage self, uint256 pos) private view returns (Checkpoint160 storage result) {
+        assembly {
+            mstore(0, self.slot)
+            result.slot := add(keccak256(0, 0x20), pos)
+        }
+    }
+
     struct History {
         Checkpoint224[] _checkpoints;
     }
@@ -230,7 +244,7 @@ library Checkpoints {
     function getAtBlock(History storage self, uint256 blockNumber) internal view returns (uint256) {
         require(blockNumber < block.number, "Checkpoints: block not yet mined");
 
-        return upperLookup(self._checkpoints, SafeCast.toUint32(blockNumber));
+        return upperLookupRecent(self._checkpoints, SafeCast.toUint32(blockNumber));
     }
 
     /**
diff --git a/scripts/generate/templates/Checkpoints.js b/scripts/generate/templates/Checkpoints.js
index dbe33610575..46404ddeaaa 100644
--- a/scripts/generate/templates/Checkpoints.js
+++ b/scripts/generate/templates/Checkpoints.js
@@ -74,7 +74,7 @@ struct Checkpoint${length} {
 
 function latest(Checkpoint${length}[] storage self) internal view returns (uint${length}) {
     uint256 pos = self.length;
-    return pos == 0 ? 0 : self[pos - 1]._value;
+    return pos == 0 ? 0 : _unsafeAccess(self, pos - 1)._value;
 }
 
 function push(
@@ -86,14 +86,14 @@ function push(
 
     if (pos > 0) {
         // Use of memory is important here.
-        Checkpoint${length} memory last = self[pos - 1];
+        Checkpoint${length} memory last = _unsafeAccess(self, pos - 1);
 
         // Checkpoints keys must be increassing.
         require(last._key <= key, "Checkpoint: invalid key");
 
         // Update or push new checkpoint
         if (last._key == key) {
-            self[pos - 1]._value = value;
+            _unsafeAccess(self, pos - 1)._value = value;
         } else {
             self.push(Checkpoint${length}({_key: key, _value: value}));
         }
@@ -107,20 +107,20 @@ function push(
 function lowerLookup(Checkpoint${length}[] storage self, uint${256 - length} key) internal view returns (uint${length}) {
     uint256 length = self.length;
     uint256 pos = _lowerDichotomicLookup(self, key, 0, length);
-    return pos == length ? 0 : self[pos]._value;
+    return pos == length ? 0 : _unsafeAccess(self, pos)._value;
 }
 
 function upperLookup(Checkpoint${length}[] storage self, uint${256 - length} key) internal view returns (uint${length}) {
     uint256 length = self.length;
     uint256 pos = _upperDichotomicLookup(self, key, 0, length);
-    return pos == 0 ? 0 : self[pos - 1]._value;
+    return pos == 0 ? 0 : _unsafeAccess(self, pos - 1)._value;
 }
 
 function upperLookupRecent(Checkpoint${length}[] storage self, uint${256 - length} key) internal view returns (uint224) {
     uint256 length = self.length;
     uint256 offset = 1;
 
-    while (offset <= length && self[length - offset]._key > key) {
+    while (offset <= length && _unsafeAccess(self, length - offset)._key > key) {
         offset <<= 1;
     }
 
@@ -128,7 +128,7 @@ function upperLookupRecent(Checkpoint${length}[] storage self, uint${256 - lengt
     uint256 high = length - (offset >> 1);
     uint256 pos = _upperDichotomicLookup(self, key, low, high);
 
-    return pos == 0 ? 0 : self[pos - 1]._value;
+    return pos == 0 ? 0 : _unsafeAccess(self, pos - 1)._value;
 }
 
 function _upperDichotomicLookup(
@@ -139,7 +139,7 @@ function _upperDichotomicLookup(
 ) private view returns (uint256) {
     while (low < high) {
         uint256 mid = Math.average(low, high);
-        if (self[mid]._key > key) {
+        if (_unsafeAccess(self, mid)._key > key) {
             high = mid;
         } else {
             low = mid + 1;
@@ -156,7 +156,7 @@ function _lowerDichotomicLookup(
 ) private view returns (uint256) {
     while (low < high) {
         uint256 mid = Math.average(low, high);
-        if (self[mid]._key < key) {
+        if (_unsafeAccess(self, mid)._key < key) {
             low = mid + 1;
         } else {
             high = mid;
@@ -164,6 +164,13 @@ function _lowerDichotomicLookup(
     }
     return high;
 }
+
+function _unsafeAccess(Checkpoint${length}[] storage self, uint256 pos) private view returns (Checkpoint${length} storage result) {
+    assembly {
+        mstore(0, self.slot)
+        result.slot := add(keccak256(0, 0x20), pos)
+    }
+}
 `;
 /* eslint-enable max-len */