diff --git a/tools/chatgui/transport/merkle_sync.c b/tools/chatgui/transport/merkle_sync.c
index 7dcb2267..00af4c84 100644
--- a/tools/chatgui/transport/merkle_sync.c
+++ b/tools/chatgui/transport/merkle_sync.c
@@ -175,8 +175,10 @@ static int _get_level_hashes(struct merkle_sync* ms, const char* ns,
     if (sqlite3_prepare_v2(db,
             "SELECT prefix64, hash FROM merkle_tree_hash"
             " WHERE namespace=? AND level=? AND prefix64>=? AND prefix64<=?"
-            " ORDER BY prefix64", -1, &stmt, NULL) != SQLITE_OK || !stmt)
+            " ORDER BY prefix64", -1, &stmt, NULL) != SQLITE_OK || !stmt) {
+        DEBUG_ERROR(DEBUG_CATEGORY_DB_SYNC, "%s: _get_level_hashes SQL error ns=%s L%d — %s", MS_ID, ns, level, sqlite3_errmsg(db));
         return -1;
+    }
     sqlite3_bind_text(stmt, 1, ns, -1, SQLITE_STATIC);
     sqlite3_bind_int(stmt, 2, (int)(level + 1));
     sqlite3_bind_int64(stmt, 3, (sqlite3_int64)prefix);
@@ -190,6 +192,8 @@ static int _get_level_hashes(struct merkle_sync* ms, const char* ns,
         memcpy(hashes[bucket], h, MT_HASH_SIZE);
     }
     sqlite3_finalize(stmt);
+    DEBUG_DEBUG(DEBUG_CATEGORY_DB_SYNC, "%s: _get_level_hashes ns=%s L%d/P%016llx bitmap=%08x",
+                MS_ID, ns, level, (unsigned long long)prefix, *bitmap);
     return 0;
 }