diff --git a/CHANGELOG.md b/CHANGELOG.md
index c0fd55e..f0f6e8d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,8 +1,10 @@
-## v1.5.1-dev
+## v1.5.1
 
 * No longer test the `setup-dart` action on pre-2.12 SDKs.
 * Upgrade JS interop code to use extension types
   (the new name for inline classes).
+* The upcoming rename of the `be` channel to `main` is now supported with
+  forward compatibility that switches when the rename happens.
 
 ## v1.5.0
 
diff --git a/dist/main.cjs b/dist/main.cjs
index 9270ce7..9d03a72 100644
--- a/dist/main.cjs
+++ b/dist/main.cjs
@@ -1,4 +1,4 @@
-// Generated by dart2js (NullSafetyMode.sound, csp, deferred-serialization, intern-composite-values), the Dart to JavaScript compiler version: 3.2.0-92.0.dev.
+// Generated by dart2js (NullSafetyMode.sound, csp, intern-composite-values), the Dart to JavaScript compiler version: 3.2.0-140.0.dev.
 // The code supports the following hooks:
 // dartPrint(message):
 //    if this function is defined it is called instead of the Dart [print]
@@ -581,7 +581,7 @@
       return error;
     },
     _unwrapNonDartException(ex) {
-      var message, number, ieErrorCode, t1, nsme, notClosure, nullCall, nullLiteralCall, undefCall, undefLiteralCall, nullProperty, undefProperty, undefLiteralProperty, match, _null = null;
+      var message, number, ieErrorCode, nsme, notClosure, nullCall, nullLiteralCall, undefCall, undefLiteralCall, nullProperty, undefProperty, undefLiteralProperty, match;
       if (!("message" in ex))
         return ex;
       message = ex.message;
@@ -591,11 +591,11 @@
         if ((B.JSInt_methods._shrOtherPositive$1(number, 16) & 8191) === 10)
           switch (ieErrorCode) {
             case 438:
-              return A.saveStackTrace(ex, A.JsNoSuchMethodError$(A.S(message) + " (Error " + ieErrorCode + ")", _null));
+              return A.saveStackTrace(ex, A.JsNoSuchMethodError$(A.S(message) + " (Error " + ieErrorCode + ")", null));
             case 445:
             case 5007:
-              t1 = A.S(message);
-              return A.saveStackTrace(ex, new A.NullError(t1 + " (Error " + ieErrorCode + ")", _null));
+              A.S(message);
+              return A.saveStackTrace(ex, new A.NullError());
           }
       }
       if (ex instanceof TypeError) {
@@ -617,41 +617,9 @@
           if (match != null) {
             match.method = "call";
             return A.saveStackTrace(ex, A.JsNoSuchMethodError$(A._asString(message), match));
-          } else {
-            match = nullCall.matchTypeError$1(message);
-            if (match == null) {
-              match = nullLiteralCall.matchTypeError$1(message);
-              if (match == null) {
-                match = undefCall.matchTypeError$1(message);
-                if (match == null) {
-                  match = undefLiteralCall.matchTypeError$1(message);
-                  if (match == null) {
-                    match = nullProperty.matchTypeError$1(message);
-                    if (match == null) {
-                      match = nullLiteralCall.matchTypeError$1(message);
-                      if (match == null) {
-                        match = undefProperty.matchTypeError$1(message);
-                        if (match == null) {
-                          match = undefLiteralProperty.matchTypeError$1(message);
-                          t1 = match != null;
-                        } else
-                          t1 = true;
-                      } else
-                        t1 = true;
-                    } else
-                      t1 = true;
-                  } else
-                    t1 = true;
-                } else
-                  t1 = true;
-              } else
-                t1 = true;
-            } else
-              t1 = true;
-            if (t1) {
-              A._asString(message);
-              return A.saveStackTrace(ex, new A.NullError(message, match == null ? _null : match.method));
-            }
+          } else if (nullCall.matchTypeError$1(message) != null || nullLiteralCall.matchTypeError$1(message) != null || undefCall.matchTypeError$1(message) != null || undefLiteralCall.matchTypeError$1(message) != null || nullProperty.matchTypeError$1(message) != null || nullLiteralCall.matchTypeError$1(message) != null || undefProperty.matchTypeError$1(message) != null || undefLiteralProperty.matchTypeError$1(message) != null) {
+            A._asString(message);
+            return A.saveStackTrace(ex, new A.NullError());
           }
         }
         return A.saveStackTrace(ex, new A.UnknownJsTypeError(typeof message == "string" ? message : ""));
@@ -666,7 +634,7 @@
           }
           return null;
         }(ex);
-        return A.saveStackTrace(ex, new A.ArgumentError(false, _null, _null, typeof message == "string" ? message.replace(/^RangeError:\s*/, "") : message));
+        return A.saveStackTrace(ex, new A.ArgumentError(false, null, null, typeof message == "string" ? message.replace(/^RangeError:\s*/, "") : message));
       }
       if (typeof InternalError == "function" && ex instanceof InternalError)
         if (typeof message == "string" && message === "too much recursion")
@@ -1241,9 +1209,7 @@
       _._method = t4;
       _._receiver = t5;
     },
-    NullError: function NullError(t0, t1) {
-      this.__js_helper$_message = t0;
-      this._method = t1;
+    NullError: function NullError() {
     },
     JsNoSuchMethodError: function JsNoSuchMethodError(t0, t1, t2) {
       this.__js_helper$_message = t0;
@@ -1636,7 +1602,7 @@
       return A.createRuntimeType(A._Universe_eval(init.typeUniverse, recipe, false));
     },
     _installSpecializedIsTest(object) {
-      var t1, unstarred, isFn, $name, predicate, testRti = this;
+      var t1, unstarred, unstarredKind, isFn, $name, predicate, testRti = this;
       if (testRti === type$.Object)
         return A._finishIsFn(testRti, object, A._isObject);
       if (!A.isStrongTopType(testRti))
@@ -1654,8 +1620,8 @@
       if (t1 === 1)
         return A._finishIsFn(testRti, object, A._isNever);
       unstarred = t1 === 6 ? testRti._primary : testRti;
-      t1 = unstarred._kind;
-      if (t1 === 8)
+      unstarredKind = unstarred._kind;
+      if (unstarredKind === 8)
         return A._finishIsFn(testRti, object, A._isFutureOr);
       if (unstarred === type$.int)
         isFn = A._isInt;
@@ -1667,7 +1633,7 @@
         isFn = unstarred === type$.bool ? A._isBool : null;
       if (isFn != null)
         return A._finishIsFn(testRti, object, isFn);
-      if (t1 === 9) {
+      if (unstarredKind === 9) {
         $name = unstarred._primary;
         if (unstarred._rest.every(A.isTopType)) {
           testRti._specializedTestResource = "$is" + $name;
@@ -1675,7 +1641,7 @@
             return A._finishIsFn(testRti, object, A._isListTestViaProperty);
           return A._finishIsFn(testRti, object, A._isTestViaProperty);
         }
-      } else if (t1 === 11) {
+      } else if (unstarredKind === 11) {
         predicate = A.createRecordTypePredicate(unstarred._primary, unstarred._rest);
         return A._finishIsFn(testRti, object, predicate == null ? A._isNever : predicate);
       }
@@ -5422,7 +5388,7 @@
     main$body(args) {
       var $async$goto = 0,
         $async$completer = A._makeAsyncAwaitCompleter(type$.dynamic),
-        $async$returnValue, $async$handler = 2, $async$currentError, sdk, flavor, raw, os, architecture, version, channel, url, toolName, sdkPath, archivePath, extractedFolder, pubCache, error, t1, t2, t3, t4, versionFilePath, exception, $async$exception;
+        $async$returnValue, $async$handler = 2, $async$currentError, sdk, flavor, raw, os, architecture, version, channel, url, toolName, sdkPath, archivePath, extractedFolder, pubCache, error, t1, t2, exception, t3, t4, versionFilePath, $async$exception, $async$exception1;
       var $async$main = A._wrapJsFunctionForAsync(function($async$errorCode, $async$result) {
         if ($async$errorCode === 1) {
           $async$currentError = $async$result;
@@ -5485,24 +5451,32 @@
               break;
             case 14:
               // then
+              $async$handler = 18;
+              channel = "main";
+              $async$goto = 21;
+              return A._asyncAwait(A.latestPublishedVersion(channel, flavor), $async$main);
+            case 21:
+              // returning from await.
+              $async$handler = 4;
+              // goto after finally
+              $async$goto = 20;
+              break;
+            case 18:
+              // catch
+              $async$handler = 17;
+              $async$exception = $async$currentError;
               channel = "be";
-              $async$goto = A.boolConversionCheck(raw) ? 17 : 19;
+              // goto after finally
+              $async$goto = 20;
               break;
             case 17:
-              // then
-              $async$result = "latest";
-              // goto join
-              $async$goto = 18;
+              // uncaught
+              // goto catch
+              $async$goto = 4;
               break;
-            case 19:
-              // else
-              $async$goto = 20;
-              return A._asyncAwait(A.latestPublishedVersion(channel, flavor), $async$main);
             case 20:
-              // returning from await.
-            case 18:
-              // join
-              version = $async$result;
+              // after finally
+              version = "latest";
               // goto join
               $async$goto = 15;
               break;
@@ -5528,35 +5502,35 @@
               url = string$.https_ + A.S(channel) + "/" + A.S(flavor) + "/" + A.S(version) + "/sdk/dartsdk-" + A.S(os) + "-" + A.S(architecture) + "-release.zip";
               toolName = A.boolConversionCheck(raw) ? "dart_raw" : "dart";
               sdkPath = !A.boolConversionCheck(raw) ? A._asString(t2._as(t1.toolCache).find(toolName, version, architecture)) : "";
-              $async$goto = J.get$length$asx(sdkPath) !== 0 ? 21 : 23;
+              $async$goto = J.get$length$asx(sdkPath) !== 0 ? 22 : 24;
               break;
-            case 21:
+            case 22:
               // then
               t2._as(t1.core).info("Using cached sdk from " + A.S(sdkPath) + ".");
               // goto join
-              $async$goto = 22;
+              $async$goto = 23;
               break;
-            case 23:
+            case 24:
               // else
               t2._as(t1.core).info(A.S(url) + " ...");
               t3 = type$.String;
-              $async$goto = 24;
+              $async$goto = 25;
               return A._asyncAwait(A.promiseToFuture(t2._as(t2._as(t1.toolCache).downloadTool(url)), t3), $async$main);
-            case 24:
+            case 25:
               // returning from await.
               archivePath = $async$result;
-              $async$goto = 25;
+              $async$goto = 26;
               return A._asyncAwait(A.promiseToFuture(t2._as(t2._as(t1.toolCache).extractZip(archivePath)), t3), $async$main);
-            case 25:
+            case 26:
               // returning from await.
               extractedFolder = $async$result;
               extractedFolder = A.join(extractedFolder, "dart-sdk");
-              $async$goto = 26;
+              $async$goto = 27;
               return A._asyncAwait(A.promiseToFuture(t2._as(t2._as(t1.toolCache).cacheDir(extractedFolder, toolName, version, architecture)), t3), $async$main);
-            case 26:
+            case 27:
               // returning from await.
               sdkPath = $async$result;
-            case 22:
+            case 23:
               // join
               t3 = t2._as(t1.process);
               t4 = J.$eq$(os, "windows") ? "USERPROFILE" : "HOME";
@@ -5567,9 +5541,9 @@
               t2._as(t1.core).addPath(A.join(sdkPath, "bin"));
               t2._as(t1.core).exportVariable("PUB_CACHE", pubCache);
               t2._as(t1.core).addPath(A.join(pubCache, "bin"));
-              $async$goto = 27;
+              $async$goto = 28;
               return A._asyncAwait(A.createPubOIDCToken(), $async$main);
-            case 27:
+            case 28:
               // returning from await.
               if (A.boolConversionCheck(raw)) {
                 t3 = t2._as(t1.core);
@@ -5577,9 +5551,9 @@
                 t3.setOutput("dart-version", B.JSString_methods.trim$0(A._asString(t2._as(t1.fs).readFileSync(versionFilePath, "utf8"))));
               } else
                 t2._as(t1.core).setOutput("dart-version", version);
-              $async$goto = 28;
+              $async$goto = 29;
               return A._asyncAwait(A.promiseToFuture(t2._as(t2._as(t1.exec).exec("dart", A._setArrayType(["--version"], type$.JSArray_String))), type$.dynamic), $async$main);
-            case 28:
+            case 29:
               // returning from await.
               $async$handler = 2;
               // goto after finally
@@ -5588,8 +5562,8 @@
             case 4:
               // catch
               $async$handler = 3;
-              $async$exception = $async$currentError;
-              error = A.unwrapException($async$exception);
+              $async$exception1 = $async$currentError;
+              error = A.unwrapException($async$exception1);
               t1 = self;
               type$.JSObject._as(t1.core).setFailed(A.S(error));
               // goto after finally
@@ -6589,10 +6563,7 @@
   };
   A.NullError.prototype = {
     toString$0(_) {
-      var t1 = this._method;
-      if (t1 == null)
-        return "NoSuchMethodError: " + this.__js_helper$_message;
-      return "NoSuchMethodError: method not found: '" + t1 + "' on null";
+      return "Null check operator used on a null value";
     }
   };
   A.JsNoSuchMethodError.prototype = {
@@ -7289,7 +7260,7 @@
         t1 = this.$ti;
       t1._bind$1($E)._eval$1("1/(2)")._as(f);
       result = new A._Future($.Zone__current, $E._eval$1("_Future<0>"));
-      this._addListener$1(new A._FutureListener(result, 3, f, onError, t1._eval$1("@<1>")._bind$1($E)._eval$1("_FutureListener<1,2>")));
+      this._addListener$1(new A._FutureListener(result, 19, f, onError, t1._eval$1("@<1>")._bind$1($E)._eval$1("_FutureListener<1,2>")));
       return result;
     },
     _setErrorObject$1(error) {
diff --git a/dist/sig.txt b/dist/sig.txt
index ce282a6..e470ffc 100644
--- a/dist/sig.txt
+++ b/dist/sig.txt
@@ -1 +1 @@
-F5AD5D9AC7CB46475A2BB056581E63C4
+C101968925A261FBCDF2AFA30D38A662
diff --git a/lib/main.dart b/lib/main.dart
index d39946e..3ea6982 100644
--- a/lib/main.dart
+++ b/lib/main.dart
@@ -51,9 +51,15 @@ void main(List<String> args) async {
       version =
           raw ? 'latest' : (await latestPublishedVersion(channel, flavor));
     } else if (sdk == 'main') {
-      channel = 'be';
-      version =
-          raw ? 'latest' : (await latestPublishedVersion(channel, flavor));
+      // Check for `main` first and fall back to `be`. This handles the channel
+      // rename from `be` to `main` (also tracked as b/299435467).
+      try {
+        channel = 'main';
+        await latestPublishedVersion(channel, flavor);
+      } catch (_) {
+        channel = 'be';
+      }
+      version = 'latest';
     } else {
       version = sdk;