diff --git a/libraries/chain/controller.cpp b/libraries/chain/controller.cpp
index 8eed9c896a..9a8329c295 100644
--- a/libraries/chain/controller.cpp
+++ b/libraries/chain/controller.cpp
@@ -1371,6 +1371,8 @@ struct controller_impl {
                   savanna_transistion_required = true;
                   // Do not advance irreversible past IF Genesis Block
                   break;
+               } else if ((*bitr)->block->is_proper_svnn_block()) {
+                  fork_db.switch_to_savanna();
                }
             }
          } catch( std::exception& ) {
@@ -1927,9 +1929,6 @@ struct controller_impl {
           [&](const block_state_legacy_ptr& head) -> block_state_pair {
              if (fork_db.version_in_use() == fork_database::in_use_t::both) {
                 return fork_db.apply_s<block_state_pair>([&](const auto& forkdb) -> block_state_pair {
-                   if (forkdb.root()->header.is_proper_svnn_block()) {
-                      return { {}, forkdb.head() }; // legacy not needed past transition
-                   }
                    return { head, forkdb.head() };
                 });
              }
diff --git a/libraries/chain/fork_database.cpp b/libraries/chain/fork_database.cpp
index e6ecf7761b..5bafbd03e9 100644
--- a/libraries/chain/fork_database.cpp
+++ b/libraries/chain/fork_database.cpp
@@ -686,13 +686,8 @@ namespace eosio::chain {
          wlog( "fork_database is in a bad state when closing; not writing out '${filename}', legacy_valid=${l}, savanna_valid=${s}",
                ("filename", fork_db_file)("l", legacy_valid)("s", savanna_valid) );
          return;
-      } else if (legacy_valid && savanna_valid) {
-         // don't write legacy if not needed
-         assert(fork_db_s.root() && fork_db_s.root()->block);
-         if (fork_db_s.root()->block->is_proper_svnn_block()) {
-            legacy_valid = false;
-            in_use_value = in_use_t::savanna;
-         }
+      } else if (legacy_valid && savanna_valid && in_use_value == in_use_t::savanna) {
+         legacy_valid = false; // don't write legacy if not needed, we delay 'clear' of legacy until close
       }
       assert( (legacy_valid  && (in_use_value == in_use_t::legacy))  ||
               (savanna_valid && (in_use_value == in_use_t::savanna)) ||
@@ -804,6 +799,11 @@ namespace eosio::chain {
       }
    }
 
+   // only called from the main thread
+   void fork_database::switch_to_savanna() {
+      in_use = in_use_t::savanna;
+   }
+
    block_branch_t fork_database::fetch_branch_from_head() const {
       return apply<block_branch_t>([&](auto& forkdb) {
          return forkdb.fetch_block_branch(forkdb.head()->id());
diff --git a/libraries/chain/include/eosio/chain/fork_database.hpp b/libraries/chain/include/eosio/chain/fork_database.hpp
index d08fad1c96..4795cf5fa8 100644
--- a/libraries/chain/include/eosio/chain/fork_database.hpp
+++ b/libraries/chain/include/eosio/chain/fork_database.hpp
@@ -156,6 +156,7 @@ namespace eosio::chain {
 
       // switches to using both legacy and savanna during transition
       void switch_from_legacy(const block_state_ptr& root);
+      void switch_to_savanna();
 
       in_use_t version_in_use() const { return in_use.load(); }