--- a/toolkit/components/places/SyncedBookmarksMirror.jsm
+++ b/toolkit/components/places/SyncedBookmarksMirror.jsm
@@ -1282,17 +1282,20 @@ class SyncedBookmarksMirror {
    * @param {Object[]} localDeletions
    *        `{ guid, level }` tuples for items to remove from Places and flag as
    *        merged.
    * @param {String[]} remoteDeletions
    *        Remotely deleted GUIDs that should be flagged as merged.
    */
   async updateLocalItemsInPlaces(mergedRoot, localDeletions, remoteDeletions) {
     MirrorLog.trace("Setting up merge states table");
-    let mergeStatesParams = Array.from(mergedRoot.mergeStatesParams());
+    let mergeStatesParams = [];
+    for await (let param of yieldingIterator(mergedRoot.mergeStatesParams())) {
+      mergeStatesParams.push(param);
+    }
     if (mergeStatesParams.length) {
       await this.db.execute(`
         INSERT INTO mergeStates(localGuid, mergedGuid, parentGuid, level,
                                 position, valueState, structureState)
         VALUES(IFNULL(:localGuid, :mergedGuid), :mergedGuid, :parentGuid,
                :level, :position, :valueState, :structureState)`,
         mergeStatesParams);
     }
@@ -1694,17 +1697,17 @@ class SyncedBookmarksMirror {
   async fetchLocalChangeRecords() {
     let changeRecords = {};
     let childRecordIdsByLocalParentId = new Map();
 
     let childGuidRows = await this.db.execute(`
       SELECT parentId, guid FROM structureToUpload
       ORDER BY parentId, position`);
 
-    for (let row of childGuidRows) {
+    for await (let row of yieldingIterator(childGuidRows)) {
       let localParentId = row.getResultByName("parentId");
       let childRecordId = PlacesSyncUtils.bookmarks.guidToRecordId(
         row.getResultByName("guid"));
       if (childRecordIdsByLocalParentId.has(localParentId)) {
         let childRecordIds = childRecordIdsByLocalParentId.get(localParentId);
         childRecordIds.push(childRecordId);
       } else {
         childRecordIdsByLocalParentId.set(localParentId, [childRecordId]);
@@ -3049,25 +3052,16 @@ class BookmarkNode {
   isFolder() {
     return this.kind == SyncedBookmarksMirror.KIND.FOLDER;
   }
 
   newerThan(otherNode) {
     return this.age < otherNode.age;
   }
 
-  * descendants() {
-    for (let node of this.children) {
-      yield node;
-      if (node.isFolder()) {
-        yield* node.descendants();
-      }
-    }
-  }
-
   /**
    * Checks if remoteNode has a kind that's compatible with this *local* node.
    * - Nodes with the same kind are always compatible.
    * - Local folders are compatible with remote livemarks, but not vice-versa
    *   (ie, remote folders are *not* compatible with local livemarks)
    * - Bookmarks and queries are always compatible.
    *
    * @return {Boolean}
@@ -3492,17 +3486,17 @@ class BookmarkMerger {
       if (!this.mentions(guid)) {
         this.deleteLocally.add(guid);
       }
     }
     return mergedRoot;
   }
 
   async subsumes(tree) {
-    for await (let guid of Async.yieldingIterator(tree.syncableGuids())) {
+    for await (let guid of yieldingIterator(tree.syncableGuids())) {
       if (!this.mentions(guid)) {
         return false;
       }
     }
     return true;
   }
 
   mentions(guid) {