diff --git a/codex/merkletree/merkletree.nim b/codex/merkletree/merkletree.nim
index 1173bcc0..9b972e88 100644
--- a/codex/merkletree/merkletree.nim
+++ b/codex/merkletree/merkletree.nim
@@ -150,8 +150,7 @@ proc merkleTreeWorker*[H, K](
     without y =? self.compress( xs[a + 2 * i], xs[a + 2 * i + 1], key = key ), err:
       return failure err
     ys[i] = y
-    # yield?
-    await sleepAsync(1.millis) # cooperative scheduling (may not be necessary)
+    await sleepAsync(1.micros) # cooperative scheduling
   if isOdd:
     const key = when isBottomLayer: K.KeyOddAndBottomLayer else: K.KeyOdd
     without y =? self.compress( xs[n], self.zero, key = key ), err:
diff --git a/codex/slots/builder/builder.nim b/codex/slots/builder/builder.nim
index 8f9ec97a..8a4abe40 100644
--- a/codex/slots/builder/builder.nim
+++ b/codex/slots/builder/builder.nim
@@ -325,6 +325,7 @@ proc init*[T, H](self: SlotsBuilder[T, H]): Future[?!void] {.async.} =
     self.verifiableTree = some tree
 
   trace "Slots builder initialized"
+  success()
 
 proc new*[T, H](
   _: type SlotsBuilder[T, H],
diff --git a/codex/utils/poseidon2digest.nim b/codex/utils/poseidon2digest.nim
index b77b4463..efc9acfe 100644
--- a/codex/utils/poseidon2digest.nim
+++ b/codex/utils/poseidon2digest.nim
@@ -55,7 +55,7 @@ proc digestTree*(
       return failure err
     leaves.add(digest)
     index += chunkSize
-    await sleepAsync(1.millis) # cooperative scheduling (may not be necessary)
+    await sleepAsync(1.micros) # cooperative scheduling
   return await Poseidon2Tree.init(leaves)
 
 proc digest*(
diff --git a/tests/codex/node/testnode.nim b/tests/codex/node/testnode.nim
index 19731bf0..5d3f78bc 100644
--- a/tests/codex/node/testnode.nim
+++ b/tests/codex/node/testnode.nim
@@ -148,12 +148,15 @@ asyncchecksuite "Test Node - Basic":
         codec = ManifestCodec).tryGet()
       protected = (await erasure.encode(manifest, 3, 2)).tryGet()
       builder = Poseidon2Builder.new(localStore, protected).tryGet()
+
+    (await builder.init()).tryGet()
+
+    let
       verifiable = (await builder.buildManifest()).tryGet()
       verifiableBlock = bt.Block.new(
         verifiable.encode().tryGet(),
         codec = ManifestCodec).tryGet()
 
-    (await builder.init()).tryGet()
     (await localStore.putBlock(manifestBlock)).tryGet()
 
     let