validation: remove BLOCK_FAILED_MASK

diff --git a/src/chain.h b/src/chain.h
index 459a83aa..c2782920 100644
--- a/src/chain.h
+++ b/src/chain.h
@@ -78,7 +78,6 @@ enum BlockStatus : uint32_t {
 
     BLOCK_FAILED_VALID       =   32, //!< stage after last reached validness failed
     BLOCK_FAILED_CHILD       =   64, //!< Unused flag that was previously set when descending from failed block
-    BLOCK_FAILED_MASK        =   BLOCK_FAILED_VALID | BLOCK_FAILED_CHILD,
 
     BLOCK_OPT_WITNESS        =   128, //!< block data in blk*.dat was received with a witness-enforcing client
 
@@ -253,7 +252,7 @@ public:
     {
         AssertLockHeld(::cs_main);
         assert(!(nUpTo & ~BLOCK_VALID_MASK)); // Only validity flags allowed.
-        if (nStatus & BLOCK_FAILED_MASK)
+        if (nStatus & BLOCK_FAILED_VALID)
             return false;
         return ((nStatus & BLOCK_VALID_MASK) >= nUpTo);
     }
@@ -264,7 +263,7 @@ public:
     {
         AssertLockHeld(::cs_main);
         assert(!(nUpTo & ~BLOCK_VALID_MASK)); // Only validity flags allowed.
-        if (nStatus & BLOCK_FAILED_MASK) return false;
+        if (nStatus & BLOCK_FAILED_VALID) return false;
 
         if ((nStatus & BLOCK_VALID_MASK) < nUpTo) {
             nStatus = (nStatus & ~BLOCK_VALID_MASK) | nUpTo;
diff --git a/src/node/blockstorage.cpp b/src/node/blockstorage.cpp
index a8d5018f..218ee222 100644
--- a/src/node/blockstorage.cpp
+++ b/src/node/blockstorage.cpp
@@ -493,7 +493,7 @@ bool BlockManager::LoadBlockIndex(const std::optional<uint256>& snapshot_blockha
             pindex->nStatus = (pindex->nStatus & ~BLOCK_FAILED_CHILD) | BLOCK_FAILED_VALID;
             m_dirty_blockindex.insert(pindex);
         }
-        if (!(pindex->nStatus & BLOCK_FAILED_MASK) && pindex->pprev && (pindex->pprev->nStatus & BLOCK_FAILED_MASK)) {
+        if (!(pindex->nStatus & BLOCK_FAILED_VALID) && pindex->pprev && (pindex->pprev->nStatus & BLOCK_FAILED_VALID)) {
             // All descendants of invalid blocks are invalid too.
             pindex->nStatus |= BLOCK_FAILED_VALID;
             m_dirty_blockindex.insert(pindex);
diff --git a/src/rpc/blockchain.cpp b/src/rpc/blockchain.cpp
index d5c99876..2b5f3bcd 100644
--- a/src/rpc/blockchain.cpp
+++ b/src/rpc/blockchain.cpp
@@ -1595,7 +1595,7 @@ static RPCHelpMan getchaintips()
         if (active_chain.Contains(block)) {
             // This block is part of the currently active chain.
             status = "active";
-        } else if (block->nStatus & BLOCK_FAILED_MASK) {
+        } else if (block->nStatus & BLOCK_FAILED_VALID) {
             // This block or one of its ancestors is invalid.
             status = "invalid";
         } else if (!block->HaveNumChainTxs()) {
diff --git a/src/rpc/mining.cpp b/src/rpc/mining.cpp
index d0efa84f..89cec6f6 100644
--- a/src/rpc/mining.cpp
+++ b/src/rpc/mining.cpp
@@ -742,7 +742,7 @@ static RPCHelpMan getblocktemplate()
             if (pindex) {
                 if (pindex->IsValid(BLOCK_VALID_SCRIPTS))
                     return "duplicate";
-                if (pindex->nStatus & BLOCK_FAILED_MASK)
+                if (pindex->nStatus & BLOCK_FAILED_VALID)
                     return "duplicate-invalid";
                 return "duplicate-inconclusive";
             }
diff --git a/src/test/blockchain_tests.cpp b/src/test/blockchain_tests.cpp
index 8c297975..d80aa836 100644
--- a/src/test/blockchain_tests.cpp
+++ b/src/test/blockchain_tests.cpp
@@ -135,7 +135,7 @@ BOOST_FIXTURE_TEST_CASE(invalidate_block, TestChain100Setup)
     auto pindex = tip_to_invalidate->pprev;
     while (pindex) {
         WITH_LOCK(::cs_main, assert(pindex->IsValid(BLOCK_VALID_TRANSACTIONS)));
-        WITH_LOCK(::cs_main, assert((pindex->nStatus & BLOCK_FAILED_MASK) == 0));
+        WITH_LOCK(::cs_main, assert((pindex->nStatus & BLOCK_FAILED_VALID) == 0));
         pindex = pindex->pprev;
     }
 
diff --git a/src/test/fuzz/block_index_tree.cpp b/src/test/fuzz/block_index_tree.cpp
index a4bbe958..5112a7e0 100644
--- a/src/test/fuzz/block_index_tree.cpp
+++ b/src/test/fuzz/block_index_tree.cpp
@@ -61,7 +61,7 @@ FUZZ_TARGET(block_index_tree, .init = initialize_block_index_tree)
                 // Receive a header building on an existing valid one. This assumes headers are valid, so PoW is not relevant here.
                 LOCK(cs_main);
                 CBlockIndex* prev_block = PickValue(fuzzed_data_provider, blocks);
-                if (!(prev_block->nStatus & BLOCK_FAILED_MASK)) {
+                if (!(prev_block->nStatus & BLOCK_FAILED_VALID)) {
                     CBlockHeader header = ConsumeBlockHeader(fuzzed_data_provider, prev_block->GetBlockHash(), nonce_counter);
                     CBlockIndex* index = blockman.AddToBlockIndex(header, chainman.m_best_header);
                     assert(index->nStatus & BLOCK_VALID_TREE);
@@ -74,7 +74,7 @@ FUZZ_TARGET(block_index_tree, .init = initialize_block_index_tree)
                 LOCK(cs_main);
                 CBlockIndex* index = PickValue(fuzzed_data_provider, blocks);
                 // Must be new to us and not known to be invalid (e.g. because of an invalid ancestor).
-                if (index->nTx == 0 && !(index->nStatus & BLOCK_FAILED_MASK)) {
+                if (index->nTx == 0 && !(index->nStatus & BLOCK_FAILED_VALID)) {
                     if (fuzzed_data_provider.ConsumeBool()) { // Invalid
                         BlockValidationState state;
                         state.Invalid(BlockValidationResult::BLOCK_CONSENSUS, "consensus-invalid");
@@ -124,7 +124,7 @@ FUZZ_TARGET(block_index_tree, .init = initialize_block_index_tree)
                     }
                     // Connect blocks, possibly fail
                     for (CBlockIndex* block : to_connect | std::views::reverse) {
-                        assert(!(block->nStatus & BLOCK_FAILED_MASK));
+                        assert(!(block->nStatus & BLOCK_FAILED_VALID));
                         assert(block->nStatus & BLOCK_HAVE_DATA);
                         if (!block->IsValid(BLOCK_VALID_SCRIPTS)) {
                             if (fuzzed_data_provider.ConsumeBool()) { // Invalid
diff --git a/src/test/fuzz/chain.cpp b/src/test/fuzz/chain.cpp
index 2c294fd5..4d3a6f42 100644
--- a/src/test/fuzz/chain.cpp
+++ b/src/test/fuzz/chain.cpp
@@ -50,7 +50,6 @@ FUZZ_TARGET(chain)
             BlockStatus::BLOCK_HAVE_UNDO,
             BlockStatus::BLOCK_HAVE_MASK,
             BlockStatus::BLOCK_FAILED_VALID,
-            BlockStatus::BLOCK_FAILED_MASK,
             BlockStatus::BLOCK_OPT_WITNESS,
         });
         if (block_status & ~BLOCK_VALID_MASK) {
diff --git a/src/validation.cpp b/src/validation.cpp
index 7dee16d9..1285edc2 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -3173,7 +3173,7 @@ CBlockIndex* Chainstate::FindMostWorkChain()
             // which block files have been deleted.  Remove those as candidates
             // for the most work chain if we come across them; we can't switch
             // to a chain unless we have all the non-active-chain parent blocks.
-            bool fFailedChain = pindexTest->nStatus & BLOCK_FAILED_MASK;
+            bool fFailedChain = pindexTest->nStatus & BLOCK_FAILED_VALID;
             bool fMissingData = !(pindexTest->nStatus & BLOCK_HAVE_DATA);
             if (fFailedChain || fMissingData) {
                 // Candidate chain is not usable (either invalid or missing data)
@@ -3590,7 +3590,7 @@ bool Chainstate::InvalidateBlock(BlockValidationState& state, CBlockIndex* pinde
             // at least as good with CBlockIndexWorkComparator as the new tip.
             if (!m_chain.Contains(candidate) &&
                 !CBlockIndexWorkComparator()(candidate, pindex->pprev) &&
-                !(candidate->nStatus & BLOCK_FAILED_MASK)) {
+                !(candidate->nStatus & BLOCK_FAILED_VALID)) {
                 highpow_outofchain_headers.insert({candidate->nChainWork, candidate});
             }
         }
@@ -3689,7 +3689,7 @@ bool Chainstate::InvalidateBlock(BlockValidationState& state, CBlockIndex* pinde
         }
 
         // Mark pindex as invalid if it never was in the main chain
-        if (!pindex_was_in_chain && !(pindex->nStatus & BLOCK_FAILED_MASK)) {
+        if (!pindex_was_in_chain && !(pindex->nStatus & BLOCK_FAILED_VALID)) {
             pindex->nStatus |= BLOCK_FAILED_VALID;
             m_blockman.m_dirty_blockindex.insert(pindex);
             setBlockIndexCandidates.erase(pindex);
@@ -3753,8 +3753,8 @@ void Chainstate::ResetBlockFailureFlags(CBlockIndex *pindex) {
 
     // Remove the invalidity flag from this block and all its descendants and ancestors.
     for (auto& [_, block_index] : m_blockman.m_block_index) {
-        if ((block_index.nStatus & BLOCK_FAILED_MASK) && (block_index.GetAncestor(nHeight) == pindex || pindex->GetAncestor(block_index.nHeight) == &block_index)) {
-            block_index.nStatus &= ~BLOCK_FAILED_MASK;
+        if ((block_index.nStatus & BLOCK_FAILED_VALID) && (block_index.GetAncestor(nHeight) == pindex || pindex->GetAncestor(block_index.nHeight) == &block_index)) {
+            block_index.nStatus &= ~BLOCK_FAILED_VALID;
             m_blockman.m_dirty_blockindex.insert(&block_index);
             if (block_index.IsValid(BLOCK_VALID_TRANSACTIONS) && block_index.HaveNumChainTxs() && setBlockIndexCandidates.value_comp()(m_chain.Tip(), &block_index)) {
                 setBlockIndexCandidates.insert(&block_index);
@@ -4237,7 +4237,7 @@ bool ChainstateManager::AcceptBlockHeader(const CBlockHeader& block, BlockValida
             CBlockIndex* pindex = &(miSelf->second);
             if (ppindex)
                 *ppindex = pindex;
-            if (pindex->nStatus & BLOCK_FAILED_MASK) {
+            if (pindex->nStatus & BLOCK_FAILED_VALID) {
                 LogDebug(BCLog::VALIDATION, "%s: block %s is marked invalid\n", __func__, hash.ToString());
                 return state.Invalid(BlockValidationResult::BLOCK_CACHED_INVALID, "duplicate-invalid",
                                      strprintf("block %s was previously marked invalid", hash.ToString()));
@@ -4258,7 +4258,7 @@ bool ChainstateManager::AcceptBlockHeader(const CBlockHeader& block, BlockValida
             return state.Invalid(BlockValidationResult::BLOCK_MISSING_PREV, "prev-blk-not-found");
         }
         pindexPrev = &((*mi).second);
-        if (pindexPrev->nStatus & BLOCK_FAILED_MASK) {
+        if (pindexPrev->nStatus & BLOCK_FAILED_VALID) {
             LogDebug(BCLog::VALIDATION, "header %s has prev block invalid: %s\n", hash.ToString(), block.hashPrevBlock.ToString());
             return state.Invalid(BlockValidationResult::BLOCK_INVALID_PREV, "bad-prevblk");
         }
@@ -4952,7 +4952,7 @@ bool ChainstateManager::LoadBlockIndex()
                     chainstate->TryAddBlockIndexCandidate(pindex);
                 }
             }
-            if (pindex->nStatus & BLOCK_FAILED_MASK && (!m_best_invalid || pindex->nChainWork > m_best_invalid->nChainWork)) {
+            if (pindex->nStatus & BLOCK_FAILED_VALID && (!m_best_invalid || pindex->nChainWork > m_best_invalid->nChainWork)) {
                 m_best_invalid = pindex;
             }
             if (pindex->IsValid(BLOCK_VALID_TREE) && (m_best_header == nullptr || CBlockIndexWorkComparator()(m_best_header, pindex)))
@@ -5192,7 +5192,7 @@ void ChainstateManager::CheckBlockIndex() const
     // are not yet validated.
     CChain best_hdr_chain;
     assert(m_best_header);
-    assert(!(m_best_header->nStatus & BLOCK_FAILED_MASK));
+    assert(!(m_best_header->nStatus & BLOCK_FAILED_VALID));
     best_hdr_chain.SetTip(*m_best_header);
 
     std::multimap<const CBlockIndex*, const CBlockIndex*> forward;
@@ -5307,9 +5307,9 @@ void ChainstateManager::CheckBlockIndex() const
         if ((pindex->nStatus & BLOCK_VALID_MASK) >= BLOCK_VALID_SCRIPTS) assert(pindexFirstNotScriptsValid == nullptr); // SCRIPTS valid implies all parents are SCRIPTS valid
         if (pindexFirstInvalid == nullptr) {
             // Checks for not-invalid blocks.
-            assert((pindex->nStatus & BLOCK_FAILED_MASK) == 0); // The failed mask cannot be set for blocks without invalid parents.
+            assert((pindex->nStatus & BLOCK_FAILED_VALID) == 0); // The failed flag cannot be set for blocks without invalid parents.
         } else {
-            assert(pindex->nStatus & BLOCK_FAILED_MASK); // Invalid blocks and their descendants must be marked as invalid
+            assert(pindex->nStatus & BLOCK_FAILED_VALID); // Invalid blocks and their descendants must be marked as invalid
         }
         // Make sure m_chain_tx_count sum is correctly computed.
         if (!pindex->pprev) {
@@ -5324,7 +5324,7 @@ void ChainstateManager::CheckBlockIndex() const
             assert((pindex->m_chain_tx_count != 0) == (pindex == snap_base));
         }
         // There should be no block with more work than m_best_header, unless it's known to be invalid
-        assert((pindex->nStatus & BLOCK_FAILED_MASK) || pindex->nChainWork <= m_best_header->nChainWork);
+        assert((pindex->nStatus & BLOCK_FAILED_VALID) || pindex->nChainWork <= m_best_header->nChainWork);
 
         // Chainstate-specific checks on setBlockIndexCandidates
         for (const auto& c : m_chainstates) {
@@ -5640,7 +5640,7 @@ util::Result<CBlockIndex*> ChainstateManager::ActivateSnapshot(
                           base_blockhash.ToString()))};
         }
 
-        bool start_block_invalid = snapshot_start_block->nStatus & BLOCK_FAILED_MASK;
+        bool start_block_invalid = snapshot_start_block->nStatus & BLOCK_FAILED_VALID;
         if (start_block_invalid) {
             return util::Error{Untranslated(strprintf("The base block header (%s) is part of an invalid chain", base_blockhash.ToString()))};
         }
@@ -6285,7 +6285,7 @@ void ChainstateManager::RecalculateBestHeader()
     AssertLockHeld(cs_main);
     m_best_header = ActiveChain().Tip();
     for (auto& entry : m_blockman.m_block_index) {
-        if (!(entry.second.nStatus & BLOCK_FAILED_MASK) && m_best_header->nChainWork < entry.second.nChainWork) {
+        if (!(entry.second.nStatus & BLOCK_FAILED_VALID) && m_best_header->nChainWork < entry.second.nChainWork) {
             m_best_header = &entry.second;
         }
     }