diff --git a/packages/incremental-merkle-tree.sol/contracts/IncrementalBinaryTree.sol b/packages/incremental-merkle-tree.sol/contracts/IncrementalBinaryTree.sol
index d9831c0..1ab197f 100644
--- a/packages/incremental-merkle-tree.sol/contracts/IncrementalBinaryTree.sol
+++ b/packages/incremental-merkle-tree.sol/contracts/IncrementalBinaryTree.sol
@@ -104,7 +104,7 @@ library IncrementalBinaryTree {
         uint256 updateIndex;
 
         for (uint8 i = 0; i < depth; ) {
-            updateIndex |= uint256(proofPathIndices[i] & 1) << uint256(i);
+            updateIndex |= uint256(proofPathIndices[i]) << uint256(i);
 
             if (proofPathIndices[i] == 0) {
                 if (proofSiblings[i] == self.lastSubtrees[i][1]) {