diff --git a/fuzz/refresh_ssl_corpora.sh b/fuzz/refresh_ssl_corpora.sh
index 6db5562..d49f574 100755
--- a/fuzz/refresh_ssl_corpora.sh
+++ b/fuzz/refresh_ssl_corpora.sh
@@ -70,8 +70,8 @@
 no_fuzzer_mode_shim=$(readlink -f \
     "$no_fuzzer_mode_build_dir/ssl/test/bssl_shim")
 
-fuzzer_mode_transcripts=$(mktemp -d '/tmp/boringssl-transcript.XXXXXX')
-no_fuzzer_mode_transcripts=$(mktemp -d '/tmp/boringssl-transcript.XXXXXX')
+fuzzer_mode_transcripts=$(mktemp -d '/tmp/boringssl-transcript-fuzzer-mode.XXXXXX')
+no_fuzzer_mode_transcripts=$(mktemp -d '/tmp/boringssl-transcript-no-fuzzer-mode.XXXXXX')
 
 echo Recording fuzzer-mode transcripts
 (cd ../ssl/test/runner/ && go test \
@@ -84,7 +84,7 @@
 (cd ../ssl/test/runner/ && go test \
     -shim-path "$no_fuzzer_mode_shim" \
     -transcript-dir "$no_fuzzer_mode_transcripts" \
-    -deterministic) || true
+    -deterministic)
 
 
 # Minimize the existing corpora.
diff --git a/ssl/test/bssl_shim.cc b/ssl/test/bssl_shim.cc
index 824dc94..f1531bd 100644
--- a/ssl/test/bssl_shim.cc
+++ b/ssl/test/bssl_shim.cc
@@ -1849,66 +1849,85 @@
   return true;
 }
 
-static bool WriteSettings(int i, const TestConfig *config,
-                          const SSL_SESSION *session) {
-  if (config->write_settings.empty()) {
+// SettingsWriter writes fuzzing inputs to a file if |write_settings| is set.
+struct SettingsWriter {
+ public:
+  SettingsWriter() {}
+
+  // Init initializes the writer for a new connection, given by |i|.  Each
+  // connection gets a unique output file.
+  bool Init(int i, const TestConfig *config, SSL_SESSION *session) {
+    if (config->write_settings.empty()) {
+      return true;
+    }
+    // Treat write_settings as a path prefix for each connection in the run.
+    char buf[DECIMAL_SIZE(int)];
+    snprintf(buf, sizeof(buf), "%d", i);
+    path_ = config->write_settings + buf;
+
+    if (!CBB_init(cbb_.get(), 64)) {
+      return false;
+    }
+
+    if (session != nullptr) {
+      uint8_t *data;
+      size_t len;
+      if (!SSL_SESSION_to_bytes(session, &data, &len)) {
+        return false;
+      }
+      bssl::UniquePtr<uint8_t> free_data(data);
+      CBB child;
+      if (!CBB_add_u16(cbb_.get(), kSessionTag) ||
+          !CBB_add_u24_length_prefixed(cbb_.get(), &child) ||
+          !CBB_add_bytes(&child, data, len) ||
+          !CBB_flush(cbb_.get())) {
+        return false;
+      }
+    }
+
+    if (config->is_server &&
+        (config->require_any_client_certificate || config->verify_peer) &&
+        !CBB_add_u16(cbb_.get(), kRequestClientCert)) {
+      return false;
+    }
+
+    if (config->tls13_variant != 0 &&
+        (!CBB_add_u16(cbb_.get(), kTLS13Variant) ||
+         !CBB_add_u8(cbb_.get(),
+                     static_cast<uint8_t>(config->tls13_variant)))) {
+      return false;
+    }
+
     return true;
   }
 
-  // Treat write_settings as a path prefix for each connection in the run.
-  char buf[DECIMAL_SIZE(int)];
-  snprintf(buf, sizeof(buf), "%d", i);
-  std::string path = config->write_settings + buf;
+  // Commit writes the buffered data to disk.
+  bool Commit() {
+    if (path_.empty()) {
+      return true;
+    }
 
-  bssl::ScopedCBB cbb;
-  if (!CBB_init(cbb.get(), 64)) {
-    return false;
-  }
-
-  if (session != nullptr) {
-    uint8_t *data;
-    size_t len;
-    if (!SSL_SESSION_to_bytes(session, &data, &len)) {
+    uint8_t *settings;
+    size_t settings_len;
+    if (!CBB_add_u16(cbb_.get(), kDataTag) ||
+        !CBB_finish(cbb_.get(), &settings, &settings_len)) {
       return false;
     }
-    bssl::UniquePtr<uint8_t> free_data(data);
-    CBB child;
-    if (!CBB_add_u16(cbb.get(), kSessionTag) ||
-        !CBB_add_u24_length_prefixed(cbb.get(), &child) ||
-        !CBB_add_bytes(&child, data, len) ||
-        !CBB_flush(cbb.get())) {
+    bssl::UniquePtr<uint8_t> free_settings(settings);
+
+    using ScopedFILE = std::unique_ptr<FILE, decltype(&fclose)>;
+    ScopedFILE file(fopen(path_.c_str(), "w"), fclose);
+    if (!file) {
       return false;
     }
+
+    return fwrite(settings, settings_len, 1, file.get()) == 1;
   }
 
-  if (config->is_server &&
-      (config->require_any_client_certificate || config->verify_peer) &&
-      !CBB_add_u16(cbb.get(), kRequestClientCert)) {
-    return false;
-  }
-
-  if (config->tls13_variant != 0 &&
-      (!CBB_add_u16(cbb.get(), kTLS13Variant) ||
-       !CBB_add_u8(cbb.get(), static_cast<uint8_t>(config->tls13_variant)))) {
-    return false;
-  }
-
-  uint8_t *settings;
-  size_t settings_len;
-  if (!CBB_add_u16(cbb.get(), kDataTag) ||
-      !CBB_finish(cbb.get(), &settings, &settings_len)) {
-    return false;
-  }
-  bssl::UniquePtr<uint8_t> free_settings(settings);
-
-  using ScopedFILE = std::unique_ptr<FILE, decltype(&fclose)>;
-  ScopedFILE file(fopen(path.c_str(), "w"), fclose);
-  if (!file) {
-    return false;
-  }
-
-  return fwrite(settings, settings_len, 1, file.get()) == 1;
-}
+ private:
+  std::string path_;
+  bssl::ScopedCBB cbb_;
+};
 
 static bssl::UniquePtr<SSL> NewSSL(SSL_CTX *ssl_ctx, const TestConfig *config,
                                    SSL_SESSION *session, bool is_resume,
@@ -2708,12 +2727,18 @@
     }
 
     bssl::UniquePtr<SSL_SESSION> offer_session = std::move(session);
-    if (!WriteSettings(i, config, offer_session.get())) {
+    SettingsWriter writer;
+    if (!writer.Init(i, config, offer_session.get())) {
       fprintf(stderr, "Error writing settings.\n");
       return 1;
     }
-    if (!DoConnection(&session, ssl_ctx.get(), config, &retry_config, is_resume,
-                      offer_session.get())) {
+    bool ok = DoConnection(&session, ssl_ctx.get(), config, &retry_config,
+                           is_resume, offer_session.get());
+    if (!writer.Commit()) {
+      fprintf(stderr, "Error writing settings.\n");
+      return 1;
+    }
+    if (!ok) {
       fprintf(stderr, "Connection %d failed.\n", i + 1);
       ERR_print_errors_fp(stderr);
       return 1;
diff --git a/ssl/test/runner/runner.go b/ssl/test/runner/runner.go
index ce20d22..866ad53 100644
--- a/ssl/test/runner/runner.go
+++ b/ssl/test/runner/runner.go
@@ -482,21 +482,23 @@
 
 var testCases []testCase
 
-func writeTranscript(test *testCase, path string, data []byte) {
+func appendTranscript(path string, data []byte) error {
 	if len(data) == 0 {
-		return
+		return nil
 	}
 
 	settings, err := ioutil.ReadFile(path)
 	if err != nil {
-		fmt.Fprintf(os.Stderr, "Error reading %s: %s.\n", path, err)
-		return
+		if !os.IsNotExist(err) {
+			return err
+		}
+		// If the shim aborted before writing a file, use a default
+		// settings block, so the transcript is still somewhat valid.
+		settings = []byte{0, 0} // kDataTag
 	}
 
 	settings = append(settings, data...)
-	if err := ioutil.WriteFile(path, settings, 0644); err != nil {
-		fmt.Fprintf(os.Stderr, "Error writing %s: %s\n", path, err)
-	}
+	return ioutil.WriteFile(path, settings, 0644)
 }
 
 // A timeoutConn implements an idle timeout on each Read and Write operation.
@@ -523,7 +525,7 @@
 	return t.Conn.Write(b)
 }
 
-func doExchange(test *testCase, config *Config, conn net.Conn, isResume bool, transcriptPrefix string, num int) error {
+func doExchange(test *testCase, config *Config, conn net.Conn, isResume bool, transcripts *[][]byte, num int) error {
 	if !test.noSessionCache {
 		if config.ClientSessionCache == nil {
 			config.ClientSessionCache = NewLRUClientSessionCache(1)
@@ -575,10 +577,13 @@
 		if *flagDebug {
 			defer connDebug.WriteTo(os.Stdout)
 		}
-		if len(transcriptPrefix) != 0 {
+		if len(*transcriptDir) != 0 {
 			defer func() {
-				path := transcriptPrefix + strconv.Itoa(num)
-				writeTranscript(test, path, connDebug.Transcript())
+				if num == len(*transcripts) {
+					*transcripts = append(*transcripts, connDebug.Transcript())
+				} else {
+					panic("transcripts are out of sync")
+				}
 			}()
 		}
 
@@ -1118,6 +1123,7 @@
 	}
 
 	var transcriptPrefix string
+	var transcripts [][]byte
 	if len(*transcriptDir) != 0 {
 		protocol := "tls"
 		if test.protocol == dtls {
@@ -1176,7 +1182,7 @@
 
 	conn, err := acceptOrWait(listener, waitChan)
 	if err == nil {
-		err = doExchange(test, &config, conn, false /* not a resumption */, transcriptPrefix, 0)
+		err = doExchange(test, &config, conn, false /* not a resumption */, &transcripts, 0)
 		conn.Close()
 	}
 
@@ -1196,7 +1202,7 @@
 		var connResume net.Conn
 		connResume, err = acceptOrWait(listener, waitChan)
 		if err == nil {
-			err = doExchange(test, &resumeConfig, connResume, true /* resumption */, transcriptPrefix, i+1)
+			err = doExchange(test, &resumeConfig, connResume, true /* resumption */, &transcripts, i+1)
 			connResume.Close()
 		}
 	}
@@ -1217,6 +1223,14 @@
 		waitTimeout.Stop()
 	}
 
+	// Now that the shim has exitted, all the settings files have been
+	// written. Append the saved transcripts.
+	for i, transcript := range transcripts {
+		if err := appendTranscript(transcriptPrefix+strconv.Itoa(i), transcript); err != nil {
+			return err
+		}
+	}
+
 	var isValgrindError, mustFail bool
 	if exitError, ok := childErr.(*exec.ExitError); ok {
 		switch exitError.Sys().(syscall.WaitStatus).ExitStatus() {