diff --git a/src/Connection/Internal/Http2ConnectionProcessor.php b/src/Connection/Internal/Http2ConnectionProcessor.php
index e76b6631..8ab79629 100644
--- a/src/Connection/Internal/Http2ConnectionProcessor.php
+++ b/src/Connection/Internal/Http2ConnectionProcessor.php
@@ -439,19 +439,24 @@ public function handleHeaders(int $streamId, array $pseudo, array $headers): voi
             $stream->trailers->promise()
         );
 
-        $requestCompletion = $stream->requestBodyCompletion;
         $stream->responsePending = false;
-        $stream->pendingResponse->resolve(call(static function () use ($response, $requestCompletion) {
-            yield $requestCompletion->promise();
+        $stream->pendingResponse->resolve(call(static function () use ($response, $stream) {
+            yield $stream->requestBodyCompletion->promise();
+
+            $stream->pendingResponse = null;
 
             return $response;
         }));
 
-        if ($this->serverWindow <= $stream->request->getBodySizeLimit() >> 1) {
-            $increment = $stream->request->getBodySizeLimit() - $this->serverWindow;
-            $this->serverWindow = $stream->request->getBodySizeLimit();
+        if ($this->serverWindow <= self::MINIMUM_WINDOW) {
+            $this->serverWindow += self::MAX_INCREMENT;
+            $this->writeFrame(self::WINDOW_UPDATE, 0, 0, \pack("N", self::MAX_INCREMENT));
+        }
+
+        if ($stream->serverWindow <= self::MINIMUM_WINDOW) {
+            $stream->serverWindow += self::MAX_INCREMENT;
 
-            $this->writeFrame(self::WINDOW_UPDATE, 0, 0, \pack("N", $increment));
+            $this->writeFrame(self::WINDOW_UPDATE, self::NO_FLAG, $streamId, \pack("N", self::MAX_INCREMENT));
         }
 
         if (isset($headers["content-length"])) {
@@ -610,6 +615,9 @@ static function () {
 
         $this->streams[$streamId] = $stream;
 
+        $stream->requestBodyComplete = true;
+        $stream->requestBodyCompletion->resolve();
+
         if ($parentStream->request->getPushHandler() === null) {
             $this->handleStreamException(new Http2StreamException("Push promise refused", $streamId, self::CANCEL));
 
@@ -957,6 +965,8 @@ public function request(Request $request, CancellationToken $cancellationToken,
                     return yield $http2stream->pendingResponse->promise();
                 }
 
+                $responsePromise = $http2stream->pendingResponse->promise();
+
                 $http2stream->requestBodyComplete = true;
                 $http2stream->requestBodyCompletion->resolve();
 
@@ -966,10 +976,12 @@ public function request(Request $request, CancellationToken $cancellationToken,
                     yield $eventListener->completeSendingRequest($request, $stream);
                 }
 
-                return yield $http2stream->pendingResponse->promise();
+                return yield $responsePromise;
             } catch (\Throwable $exception) {
                 if (isset($this->streams[$streamId])) {
-                    $http2stream->requestBodyCompletion->fail($exception);
+                    if (!$http2stream->requestBodyComplete) {
+                        $http2stream->requestBodyCompletion->fail($exception);
+                    }
 
                     $this->releaseStream($streamId, $exception);
                 }
@@ -1015,16 +1027,9 @@ private function run(): \Generator
             $parser = (new Http2Parser($this))->parse();
 
             while (null !== $chunk = yield $this->socket->read()) {
-                $promise = $parser->send($chunk);
-
-                \assert($promise === null || $promise instanceof Promise);
-
-                while ($promise instanceof Promise) {
-                    yield $promise; // Wait for promise to resolve before resuming parser and reading more data.
-                    $promise = $parser->send(null);
+                $return = $parser->send($chunk);
 
-                    \assert($promise === null || $promise instanceof Promise);
-                }
+                \assert($return === null);
             }
 
             $this->shutdown(null);
@@ -1194,33 +1199,29 @@ private function releaseStream(int $streamId, ?\Throwable $exception = null): vo
 
         $stream = $this->streams[$streamId];
 
+        $exception = $exception ?? new Http2StreamException(
+            "Stream closed unexpectedly",
+            $streamId,
+            self::INTERNAL_ERROR
+        );
+
         if ($stream->responsePending) {
             $stream->responsePending = false;
-            $stream->pendingResponse->fail($exception ?? new Http2StreamException(
-                "Stream closed unexpectedly",
-                $streamId,
-                self::INTERNAL_ERROR
-            ));
+            $pendingResponse = $stream->pendingResponse;
+            $stream->pendingResponse = null;
+            $pendingResponse->fail($exception);
         }
 
         if ($stream->body) {
             $body = $stream->body;
             $stream->body = null;
-            $body->fail($exception ?? new Http2StreamException(
-                "Stream closed unexpectedly",
-                $streamId,
-                self::INTERNAL_ERROR
-            ));
+            $body->fail($exception);
         }
 
         if ($stream->trailers) {
             $trailers = $stream->trailers;
             $stream->trailers = null;
-            $trailers->fail($exception ?? new Http2StreamException(
-                "Stream closed unexpectedly",
-                $streamId,
-                self::INTERNAL_ERROR
-            ));
+            $trailers->fail($exception);
         }
 
         unset($this->streams[$streamId]);