# MutantHub mutant #4259: Logical operator mutation at validation.cpp:5109
# Repository: bitcoin/bitcoin @ ddea9196493d3b8fd841a36a6c53efd85dac7a05
# File: src/validation.cpp:5109-5109
# Review: APPROVED; outcome: KILLED
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -5109,1 +5109,1 @@
-                    if (hash != params.GetConsensus().hashGenesisBlock && !m_blockman.LookupBlockIndex(header.hashPrevBlock)) {
+                    if (hash != params.GetConsensus().hashGenesisBlock || !m_blockman.LookupBlockIndex(header.hashPrevBlock)) {