diff --git a/packages/react-dom-bindings/src/server/ReactFizzConfigDOM.js b/packages/react-dom-bindings/src/server/ReactFizzConfigDOM.js
index 91baeef4a1bff..515145f486c47 100644
--- a/packages/react-dom-bindings/src/server/ReactFizzConfigDOM.js
+++ b/packages/react-dom-bindings/src/server/ReactFizzConfigDOM.js
@@ -119,6 +119,12 @@ const SentClientRenderFunction /*         */ = 0b00100;
 const SentStyleInsertionFunction /*       */ = 0b01000;
 const SentFormReplayingRuntime /*         */ = 0b10000;
 
+type Parts = number;
+const NoParts /*                          */ = 0b00000;
+const HasShell /*                         */ = 0b00001;
+const HasHTML /*                          */ = 0b00010;
+const HasBody /*                          */ = 0b00100;
+
 // Per request, global state that is not contextual to the rendering subtree.
 // This cannot be resumed and therefore should only contain things that are
 // temporary working state or are never used in the prerender pass.
@@ -245,9 +251,8 @@ export type ResumableState = {
   // state for script streaming format, unused if using external runtime / data
   instructions: InstructionState,
 
-  // postamble state
-  hasBody: boolean,
-  hasHtml: boolean,
+  // preamble & postamble state
+  parts: Parts,
 
   // Resources - Request local cache
   unknownResources: {
@@ -637,8 +642,7 @@ export function createResumableState(
     bootstrapScripts,
     bootstrapModules,
     instructions: NothingSent,
-    hasBody: false,
-    hasHtml: false,
+    parts: NoParts,
 
     // @TODO add bootstrap script to implicit preloads
 
@@ -665,8 +669,8 @@ export function resetResumableState(
   // Resets the resumable state based on what didn't manage to fully flush in the render state.
   // This currently assumes nothing was flushed.
   resumableState.nextFormID = 0;
-  resumableState.hasBody = false;
-  resumableState.hasHtml = false;
+  resumableState.instructions = NothingSent;
+  resumableState.parts = NoParts;
   resumableState.unknownResources = {
     font: renderState.resets.font,
   };
@@ -681,6 +685,7 @@ export function resetResumableState(
 
 export function completeResumableState(resumableState: ResumableState): void {
   // This function is called when we have completed a prerender and there is a shell.
+  resumableState.parts |= HasShell;
   resumableState.bootstrapScriptContent = undefined;
   resumableState.bootstrapScripts = undefined;
   resumableState.bootstrapModules = undefined;
@@ -3708,14 +3713,14 @@ export function pushEndInstance(
     // we won't emit any more tags
     case 'body': {
       if (formatContext.insertionMode <= HTML_HTML_MODE) {
-        resumableState.hasBody = true;
+        resumableState.parts |= HasBody;
         return;
       }
       break;
     }
     case 'html':
       if (formatContext.insertionMode === ROOT_HTML_MODE) {
-        resumableState.hasHtml = true;
+        resumableState.parts |= HasHTML;
         return;
       }
       break;
@@ -4602,6 +4607,8 @@ export function writePreamble(
   renderState: RenderState,
   willFlushAllSegments: boolean,
 ): void {
+  resumableState.parts |= HasShell;
+
   // This function must be called exactly once on every request
   if (
     enableFizzExternalRuntime &&
@@ -4707,6 +4714,11 @@ export function writeHoistables(
   resumableState: ResumableState,
   renderState: RenderState,
 ): void {
+  if ((resumableState.parts & HasShell) === NoParts) {
+    // We can't write anything until we've written the shell.
+    return;
+  }
+
   let i = 0;
 
   // Emit high priority Hoistables
@@ -4759,10 +4771,10 @@ export function writePostamble(
   destination: Destination,
   resumableState: ResumableState,
 ): void {
-  if (resumableState.hasBody) {
+  if (resumableState.parts & HasBody) {
     writeChunk(destination, endChunkForTag('body'));
   }
-  if (resumableState.hasHtml) {
+  if (resumableState.parts & HasHTML) {
     writeChunk(destination, endChunkForTag('html'));
   }
 }
diff --git a/packages/react-server/src/ReactFizzServer.js b/packages/react-server/src/ReactFizzServer.js
index 7ba6f334e759a..af2b85d543bd6 100644
--- a/packages/react-server/src/ReactFizzServer.js
+++ b/packages/react-server/src/ReactFizzServer.js
@@ -4057,17 +4057,15 @@ function flushCompletedQueues(
     // that item fully and then yield. At that point we remove the already completed
     // items up until the point we completed them.
 
-    if (request.pendingRootTasks > 0) {
-      // When there are pending root tasks we don't want to flush anything
-      return;
-    }
-
     let i;
     const completedRootSegment = request.completedRootSegment;
     if (completedRootSegment !== null) {
       if (completedRootSegment.status === POSTPONED) {
         // We postponed the root, so we write nothing.
         return;
+      } else if (request.pendingRootTasks > 0) {
+        // The root is blocked on additional tasks.
+        return;
       }
 
       flushPreamble(request, destination, completedRootSegment);