diff --git a/httpcore5-h2/src/main/java/org/apache/hc/core5/http2/impl/nio/AbstractH2StreamMultiplexer.java b/httpcore5-h2/src/main/java/org/apache/hc/core5/http2/impl/nio/AbstractH2StreamMultiplexer.java
index e6b6c7a0c..f7de865a6 100644
--- a/httpcore5-h2/src/main/java/org/apache/hc/core5/http2/impl/nio/AbstractH2StreamMultiplexer.java
+++ b/httpcore5-h2/src/main/java/org/apache/hc/core5/http2/impl/nio/AbstractH2StreamMultiplexer.java
@@ -188,6 +188,7 @@ public String getId() {
 
     abstract H2StreamHandler createRemotelyInitiatedStream(
             H2StreamChannel channel,
+
             HttpProcessor httpProcessor,
             BasicHttpConnectionMetrics connMetrics,
             HandlerFactory<AsyncPushConsumer> pushHandlerFactory) throws IOException;
@@ -211,6 +212,15 @@ private int updateWindow(final AtomicInteger window, final int delta) throws Ari
         }
     }
 
+    private int updateWindowMax(final AtomicInteger window) throws ArithmeticException {
+        for (;;) {
+            final int current = window.get();
+            if (window.compareAndSet(current, Integer.MAX_VALUE)) {
+                return Integer.MAX_VALUE - current;
+            }
+        }
+    }
+
     private int updateInputWindow(
             final int streamId, final AtomicInteger window, final int delta) throws ArithmeticException {
         final int newSize = updateWindow(window, delta);
@@ -371,9 +381,9 @@ private void incrementInputCapacity(
             final int remainingCapacity = Integer.MAX_VALUE - streamWinSize;
             final int chunk = Math.min(inputCapacity, remainingCapacity);
             if (chunk != 0) {
+                updateInputWindow(streamId, inputWindow, chunk);
                 final RawFrame windowUpdateFrame = frameFactory.createWindowUpdate(streamId, chunk);
                 commitFrame(windowUpdateFrame);
-                updateInputWindow(streamId, inputWindow, chunk);
             }
         }
     }
@@ -412,7 +422,7 @@ public final void onConnect() throws HttpException, IOException {
 
         commitFrame(settingsFrame);
         localSettingState = SettingsHandshake.TRANSMITTED;
-        maximizeConnWindow(connInputWindow.get());
+        maximizeWindow(0, connInputWindow);
 
         if (streamListener != null) {
             final int initInputWindow = connInputWindow.get();
@@ -1024,7 +1034,7 @@ private void consumeDataFrame(final RawFrame frame, final H2Stream stream) throw
             }
             final int connWinSize = updateInputWindow(0, connInputWindow, -frameLength);
             if (connWinSize < CONNECTION_WINDOW_LOW_MARK) {
-                maximizeConnWindow(connWinSize);
+                maximizeWindow(0, connInputWindow);
             }
         }
         if (stream.isRemoteClosed()) {
@@ -1039,12 +1049,11 @@ private void consumeDataFrame(final RawFrame frame, final H2Stream stream) throw
         stream.consumeData(payload);
     }
 
-    private void maximizeConnWindow(final int connWinSize) throws IOException {
-        final int delta = Integer.MAX_VALUE - connWinSize;
+    private void maximizeWindow(final int streamId, final AtomicInteger window) throws IOException {
+        final int delta = updateWindowMax(window);
         if (delta > 0) {
-            final RawFrame windowUpdateFrame = frameFactory.createWindowUpdate(0, delta);
+            final RawFrame windowUpdateFrame = frameFactory.createWindowUpdate(streamId, delta);
             commitFrame(windowUpdateFrame);
-            updateInputWindow(0, connInputWindow, delta);
         }
     }