diff --git a/src/txn.c b/src/txn.c
index 9b70367e..8031a9c3 100644
--- a/src/txn.c
+++ b/src/txn.c
@@ -87,6 +87,43 @@ static bool txn_check_overlapped(lck_t *const lck, const uint32_t pid, const uin
   return false;
 }
 
+typedef struct seq_latch_result {
+  int err;
+  uint32_t seq;
+} slr_t;
+
+__cold static slr_t latch_maindb_locked(MDBX_txn *txn, MDBX_env *const env) {
+  slr_t slr = {.err = MDBX_SUCCESS, .seq = atomic_load32(&env->dbi_seqs[MAIN_DBI], mo_AcquireRelease)};
+  if (env->dbs_flags[MAIN_DBI] & DB_VALID /* Флаги MainDB уже были загружены? */) {
+    /* Читаем и проверяем повторно после захвата dbi-блокировки */
+    if (env->dbs_flags[MAIN_DBI] == (DB_VALID | txn->dbs[MAIN_DBI].flags))
+      return slr;
+    if (env->basal_txn && env->txn != txn) {
+      /* Параллельно выполняется пишущая транзакция, которая вероятно и произвела изменение MainDB.
+       * Как-либо отказаться от использования новых атрибутов в рамках текущего процесса невозможно. */
+      ERROR("MainDB db-flags changes 0x%x -> 0x%x ahead of read-txn %" PRIaTXN, txn->dbs[MAIN_DBI].flags,
+            env->dbs_flags[MAIN_DBI] & ~DB_VALID, txn->txnid);
+      slr.err = MDBX_INCOMPATIBLE;
+      return slr;
+    }
+
+    NOTICE("renew MainDB for %s-txn %" PRIaTXN " since db-flags changes 0x%x -> 0x%x",
+           (txn->flags & MDBX_TXN_RDONLY) ? "ro" : "rw", txn->txnid, env->dbs_flags[MAIN_DBI] & ~DB_VALID,
+           txn->dbs[MAIN_DBI].flags);
+    slr.seq = dbi_seq_next(env, MAIN_DBI);
+    env->dbs_flags[MAIN_DBI] = DB_POISON;
+    atomic_store32(&env->dbi_seqs[MAIN_DBI], slr.seq, mo_AcquireRelease);
+  }
+
+  slr.err = tbl_setup(env, &env->kvs[MAIN_DBI], &txn->dbs[MAIN_DBI]);
+  if (likely(slr.seq == MDBX_SUCCESS)) {
+    slr.seq = dbi_seq_next(env, MAIN_DBI);
+    env->dbs_flags[MAIN_DBI] = DB_VALID | txn->dbs[MAIN_DBI].flags;
+    atomic_store32(&env->dbi_seqs[MAIN_DBI], slr.seq, mo_AcquireRelease);
+  }
+  return slr;
+}
+
 int txn_renew(MDBX_txn *txn, unsigned flags) {
   MDBX_env *const env = txn->env;
   int rc;
@@ -156,53 +193,18 @@ int txn_renew(MDBX_txn *txn, unsigned flags) {
   txn->dbi_seqs[MAIN_DBI] = atomic_load32(&env->dbi_seqs[MAIN_DBI], mo_AcquireRelease);
 
   if (unlikely(env->dbs_flags[MAIN_DBI] != (DB_VALID | txn->dbs[MAIN_DBI].flags) || !txn->dbi_seqs[MAIN_DBI])) {
-    const bool need_txn_lock = env->basal_txn && env->basal_txn->owner != osal_thread_self();
-    bool should_unlock = false;
-    if (need_txn_lock) {
-      rc = lck_txn_lock(env, true);
-      if (rc == MDBX_SUCCESS)
-        should_unlock = true;
-      else if (rc != MDBX_BUSY && rc != MDBX_EDEADLK)
-        goto bailout;
-    }
     rc = osal_fastmutex_acquire(&env->dbi_lock);
-    if (likely(rc == MDBX_SUCCESS)) {
-      /* проверяем повторно после захвата блокировки */
-      uint32_t seq = atomic_load32(&env->dbi_seqs[MAIN_DBI], mo_AcquireRelease);
-      if (env->dbs_flags[MAIN_DBI] != (DB_VALID | txn->dbs[MAIN_DBI].flags)) {
-        if (!(env->dbs_flags[MAIN_DBI] & DB_VALID) || !need_txn_lock || should_unlock ||
-            /* если нет активной пишущей транзакции, * то следующая будет ждать на dbi_lock */ !env->txn) {
-          if (env->dbs_flags[MAIN_DBI] & DB_VALID) {
-            NOTICE("renew MainDB for %s-txn %" PRIaTXN " since db-flags changes 0x%x -> 0x%x",
-                   (txn->flags & MDBX_TXN_RDONLY) ? "ro" : "rw", txn->txnid, env->dbs_flags[MAIN_DBI] & ~DB_VALID,
-                   txn->dbs[MAIN_DBI].flags);
-            seq = dbi_seq_next(env, MAIN_DBI);
-            env->dbs_flags[MAIN_DBI] = DB_POISON;
-            atomic_store32(&env->dbi_seqs[MAIN_DBI], seq, mo_AcquireRelease);
-          }
-          rc = tbl_setup(env, &env->kvs[MAIN_DBI], &txn->dbs[MAIN_DBI]);
-          if (likely(rc == MDBX_SUCCESS)) {
-            seq = dbi_seq_next(env, MAIN_DBI);
-            env->dbs_flags[MAIN_DBI] = DB_VALID | txn->dbs[MAIN_DBI].flags;
-            atomic_store32(&env->dbi_seqs[MAIN_DBI], seq, mo_AcquireRelease);
-          }
-        } else {
-          ERROR("MainDB db-flags changes 0x%x -> 0x%x ahead of read-txn "
-                "%" PRIaTXN,
-                txn->dbs[MAIN_DBI].flags, env->dbs_flags[MAIN_DBI] & ~DB_VALID, txn->txnid);
-          rc = MDBX_INCOMPATIBLE;
-        }
-      }
-      txn->dbi_seqs[MAIN_DBI] = seq;
-      ENSURE(env, osal_fastmutex_release(&env->dbi_lock) == MDBX_SUCCESS);
-    } else {
-      DEBUG("dbi_lock failed, err %d", rc);
-    }
-    if (should_unlock)
-      lck_txn_unlock(env);
-    if (unlikely(rc != MDBX_SUCCESS))
+    if (unlikely(rc != MDBX_SUCCESS)) {
+      ERROR("dbi_lock failed, err %d", rc);
       goto bailout;
+    }
+    slr_t slr = latch_maindb_locked(txn, env);
+    ENSURE(env, osal_fastmutex_release(&env->dbi_lock) == MDBX_SUCCESS);
+    if (unlikely((rc = slr.err) != MDBX_SUCCESS))
+      goto bailout;
+    txn->dbi_seqs[MAIN_DBI] = slr.seq;
   }
+  tASSERT(txn, check_table_flags(txn->dbs[MAIN_DBI].flags) && txn->dbi_seqs[MAIN_DBI]);
 
   if (unlikely(txn->dbs[FREE_DBI].flags != MDBX_INTEGERKEY)) {
     ERROR("unexpected/invalid db-flags 0x%x for %s", txn->dbs[FREE_DBI].flags, "GC/FreeDB");
@@ -210,8 +212,6 @@ int txn_renew(MDBX_txn *txn, unsigned flags) {
     goto bailout;
   }
 
-  tASSERT(txn, txn->dbs[FREE_DBI].flags == MDBX_INTEGERKEY);
-  tASSERT(txn, check_table_flags(txn->dbs[MAIN_DBI].flags));
   if (unlikely(env->flags & ENV_FATAL_ERROR)) {
     WARNING("%s", "environment had fatal error, must shutdown!");
     rc = MDBX_PANIC;