diff --git a/clients/client-ec2-instance-connect/README.md b/clients/client-ec2-instance-connect/README.md
index 002923b44fac..9502c92caf6e 100644
--- a/clients/client-ec2-instance-connect/README.md
+++ b/clients/client-ec2-instance-connect/README.md
@@ -6,9 +6,16 @@
 
 AWS SDK for JavaScript EC2InstanceConnect Client for Node.js, Browser and React Native.
 
-<p>Amazon EC2 Instance Connect enables system administrators to publish one-time use SSH
-public keys to EC2, providing users a simple and secure way to connect to their
-instances.</p>
+<p>This is the <i> Amazon EC2 Instance Connect API Reference</i>. It
+provides descriptions, syntax, and usage examples for each of the actions for Amazon EC2
+Instance Connect. Amazon EC2 Instance Connect enables system administrators to publish
+one-time use SSH public keys to EC2, providing users a simple and secure way to connect
+to their instances.</p>
+<p>To view the Amazon EC2 Instance Connect content in the <i> Amazon EC2 User
+Guide</i>, see <a href="https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/Connect-using-EC2-Instance-Connect.html">Connect to
+your Linux instance using EC2 Instance Connect</a>.</p>
+<p>For Amazon EC2 APIs, see the <a href="https://docs.aws.amazon.com/AWSEC2/latest/APIReference/Welcome.html">Amazon EC2 API
+Reference</a>.</p>
 
 ## Installing
 
diff --git a/clients/client-ec2-instance-connect/src/EC2InstanceConnect.ts b/clients/client-ec2-instance-connect/src/EC2InstanceConnect.ts
index 48b5ca6e8254..2cb09039fecb 100644
--- a/clients/client-ec2-instance-connect/src/EC2InstanceConnect.ts
+++ b/clients/client-ec2-instance-connect/src/EC2InstanceConnect.ts
@@ -57,9 +57,16 @@ export interface EC2InstanceConnect {
 
 /**
  * @public
- * <p>Amazon EC2 Instance Connect enables system administrators to publish one-time use SSH
- *             public keys to EC2, providing users a simple and secure way to connect to their
- *             instances.</p>
+ * <p>This is the <i> Amazon EC2 Instance Connect API Reference</i>. It
+ *             provides descriptions, syntax, and usage examples for each of the actions for Amazon EC2
+ *             Instance Connect. Amazon EC2 Instance Connect enables system administrators to publish
+ *             one-time use SSH public keys to EC2, providing users a simple and secure way to connect
+ *             to their instances.</p>
+ *         <p>To view the Amazon EC2 Instance Connect content in the <i> Amazon EC2 User
+ *                 Guide</i>, see <a href="https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/Connect-using-EC2-Instance-Connect.html">Connect to
+ *                 your Linux instance using EC2 Instance Connect</a>.</p>
+ *         <p>For Amazon EC2 APIs, see the <a href="https://docs.aws.amazon.com/AWSEC2/latest/APIReference/Welcome.html">Amazon EC2 API
+ *                 Reference</a>.</p>
  */
 export class EC2InstanceConnect extends EC2InstanceConnectClient implements EC2InstanceConnect {}
 createAggregatedClient(commands, EC2InstanceConnect);
diff --git a/clients/client-ec2-instance-connect/src/EC2InstanceConnectClient.ts b/clients/client-ec2-instance-connect/src/EC2InstanceConnectClient.ts
index ab1c4c5dd1dd..02a825ef7c95 100644
--- a/clients/client-ec2-instance-connect/src/EC2InstanceConnectClient.ts
+++ b/clients/client-ec2-instance-connect/src/EC2InstanceConnectClient.ts
@@ -252,9 +252,16 @@ export interface EC2InstanceConnectClientResolvedConfig extends EC2InstanceConne
 
 /**
  * @public
- * <p>Amazon EC2 Instance Connect enables system administrators to publish one-time use SSH
- *             public keys to EC2, providing users a simple and secure way to connect to their
- *             instances.</p>
+ * <p>This is the <i> Amazon EC2 Instance Connect API Reference</i>. It
+ *             provides descriptions, syntax, and usage examples for each of the actions for Amazon EC2
+ *             Instance Connect. Amazon EC2 Instance Connect enables system administrators to publish
+ *             one-time use SSH public keys to EC2, providing users a simple and secure way to connect
+ *             to their instances.</p>
+ *         <p>To view the Amazon EC2 Instance Connect content in the <i> Amazon EC2 User
+ *                 Guide</i>, see <a href="https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/Connect-using-EC2-Instance-Connect.html">Connect to
+ *                 your Linux instance using EC2 Instance Connect</a>.</p>
+ *         <p>For Amazon EC2 APIs, see the <a href="https://docs.aws.amazon.com/AWSEC2/latest/APIReference/Welcome.html">Amazon EC2 API
+ *                 Reference</a>.</p>
  */
 export class EC2InstanceConnectClient extends __Client<
   __HttpHandlerOptions,
diff --git a/clients/client-ec2-instance-connect/src/commands/SendSerialConsoleSSHPublicKeyCommand.ts b/clients/client-ec2-instance-connect/src/commands/SendSerialConsoleSSHPublicKeyCommand.ts
index 97a2682bed15..aedadec00296 100644
--- a/clients/client-ec2-instance-connect/src/commands/SendSerialConsoleSSHPublicKeyCommand.ts
+++ b/clients/client-ec2-instance-connect/src/commands/SendSerialConsoleSSHPublicKeyCommand.ts
@@ -99,6 +99,9 @@ export interface SendSerialConsoleSSHPublicKeyCommandOutput
  * @throws {@link SerialConsoleSessionUnavailableException} (server fault)
  *  <p>Unable to start a serial console session. Please try again.</p>
  *
+ * @throws {@link SerialConsoleSessionUnsupportedException} (client fault)
+ *  <p>Your instance's BIOS version is unsupported for serial console connection. Reboot your instance to update its BIOS, and then try again to connect.</p>
+ *
  * @throws {@link ServiceException} (server fault)
  *  <p>The service encountered an error. Follow the instructions in the error message and try again.</p>
  *
diff --git a/clients/client-ec2-instance-connect/src/index.ts b/clients/client-ec2-instance-connect/src/index.ts
index d2e95c96ab86..95fa5328186a 100644
--- a/clients/client-ec2-instance-connect/src/index.ts
+++ b/clients/client-ec2-instance-connect/src/index.ts
@@ -1,9 +1,16 @@
 // smithy-typescript generated code
 /* eslint-disable */
 /**
- * <p>Amazon EC2 Instance Connect enables system administrators to publish one-time use SSH
- *             public keys to EC2, providing users a simple and secure way to connect to their
- *             instances.</p>
+ * <p>This is the <i> Amazon EC2 Instance Connect API Reference</i>. It
+ *             provides descriptions, syntax, and usage examples for each of the actions for Amazon EC2
+ *             Instance Connect. Amazon EC2 Instance Connect enables system administrators to publish
+ *             one-time use SSH public keys to EC2, providing users a simple and secure way to connect
+ *             to their instances.</p>
+ *         <p>To view the Amazon EC2 Instance Connect content in the <i> Amazon EC2 User
+ *                 Guide</i>, see <a href="https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/Connect-using-EC2-Instance-Connect.html">Connect to
+ *                 your Linux instance using EC2 Instance Connect</a>.</p>
+ *         <p>For Amazon EC2 APIs, see the <a href="https://docs.aws.amazon.com/AWSEC2/latest/APIReference/Welcome.html">Amazon EC2 API
+ *                 Reference</a>.</p>
  *
  * @packageDocumentation
  */
diff --git a/clients/client-ec2-instance-connect/src/models/models_0.ts b/clients/client-ec2-instance-connect/src/models/models_0.ts
index eaf21a0e376b..d7ed8ec2cbf7 100644
--- a/clients/client-ec2-instance-connect/src/models/models_0.ts
+++ b/clients/client-ec2-instance-connect/src/models/models_0.ts
@@ -249,6 +249,28 @@ export class SerialConsoleSessionUnavailableException extends __BaseException {
   }
 }
 
+/**
+ * @public
+ * <p>Your instance's BIOS version is unsupported for serial console connection. Reboot your instance to update its BIOS, and then try again to connect.</p>
+ */
+export class SerialConsoleSessionUnsupportedException extends __BaseException {
+  readonly name: "SerialConsoleSessionUnsupportedException" = "SerialConsoleSessionUnsupportedException";
+  readonly $fault: "client" = "client";
+  Message?: string;
+  /**
+   * @internal
+   */
+  constructor(opts: __ExceptionOptionType<SerialConsoleSessionUnsupportedException, __BaseException>) {
+    super({
+      name: "SerialConsoleSessionUnsupportedException",
+      $fault: "client",
+      ...opts,
+    });
+    Object.setPrototypeOf(this, SerialConsoleSessionUnsupportedException.prototype);
+    this.Message = opts.Message;
+  }
+}
+
 /**
  * @public
  * <p>The service encountered an error. Follow the instructions in the error message and try again.</p>
diff --git a/clients/client-ec2-instance-connect/src/protocols/Aws_json1_1.ts b/clients/client-ec2-instance-connect/src/protocols/Aws_json1_1.ts
index 24c4ed418095..1f4054c6de10 100644
--- a/clients/client-ec2-instance-connect/src/protocols/Aws_json1_1.ts
+++ b/clients/client-ec2-instance-connect/src/protocols/Aws_json1_1.ts
@@ -32,6 +32,7 @@ import {
   SerialConsoleAccessDisabledException,
   SerialConsoleSessionLimitExceededException,
   SerialConsoleSessionUnavailableException,
+  SerialConsoleSessionUnsupportedException,
   ServiceException,
   ThrottlingException,
 } from "../models/models_0";
@@ -139,6 +140,9 @@ const de_CommandError = async (output: __HttpResponse, context: __SerdeContext):
     case "SerialConsoleSessionUnavailableException":
     case "com.amazonaws.ec2instanceconnect#SerialConsoleSessionUnavailableException":
       throw await de_SerialConsoleSessionUnavailableExceptionRes(parsedOutput, context);
+    case "SerialConsoleSessionUnsupportedException":
+    case "com.amazonaws.ec2instanceconnect#SerialConsoleSessionUnsupportedException":
+      throw await de_SerialConsoleSessionUnsupportedExceptionRes(parsedOutput, context);
     case "ServiceException":
     case "com.amazonaws.ec2instanceconnect#ServiceException":
       throw await de_ServiceExceptionRes(parsedOutput, context);
@@ -296,6 +300,22 @@ const de_SerialConsoleSessionUnavailableExceptionRes = async (
   return __decorateServiceException(exception, body);
 };
 
+/**
+ * deserializeAws_json1_1SerialConsoleSessionUnsupportedExceptionRes
+ */
+const de_SerialConsoleSessionUnsupportedExceptionRes = async (
+  parsedOutput: any,
+  context: __SerdeContext
+): Promise<SerialConsoleSessionUnsupportedException> => {
+  const body = parsedOutput.body;
+  const deserialized: any = _json(body);
+  const exception = new SerialConsoleSessionUnsupportedException({
+    $metadata: deserializeMetadata(parsedOutput),
+    ...deserialized,
+  });
+  return __decorateServiceException(exception, body);
+};
+
 /**
  * deserializeAws_json1_1ServiceExceptionRes
  */
@@ -348,6 +368,8 @@ const de_ThrottlingExceptionRes = async (parsedOutput: any, context: __SerdeCont
 
 // de_SerialConsoleSessionUnavailableException omitted.
 
+// de_SerialConsoleSessionUnsupportedException omitted.
+
 // de_ServiceException omitted.
 
 // de_ThrottlingException omitted.
diff --git a/codegen/sdk-codegen/aws-models/ec2-instance-connect.json b/codegen/sdk-codegen/aws-models/ec2-instance-connect.json
index 295d5658bf55..63b53db67cb0 100644
--- a/codegen/sdk-codegen/aws-models/ec2-instance-connect.json
+++ b/codegen/sdk-codegen/aws-models/ec2-instance-connect.json
@@ -52,7 +52,7 @@
           "name": "ec2-instance-connect"
         },
         "aws.protocols#awsJson1_1": {},
-        "smithy.api#documentation": "<p>Amazon EC2 Instance Connect enables system administrators to publish one-time use SSH\n            public keys to EC2, providing users a simple and secure way to connect to their\n            instances.</p>",
+        "smithy.api#documentation": "<p>This is the <i> Amazon EC2 Instance Connect API Reference</i>. It\n            provides descriptions, syntax, and usage examples for each of the actions for Amazon EC2\n            Instance Connect. Amazon EC2 Instance Connect enables system administrators to publish\n            one-time use SSH public keys to EC2, providing users a simple and secure way to connect\n            to their instances.</p>\n        <p>To view the Amazon EC2 Instance Connect content in the <i> Amazon EC2 User\n                Guide</i>, see <a href=\"https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/Connect-using-EC2-Instance-Connect.html\">Connect to\n                your Linux instance using EC2 Instance Connect</a>.</p>\n        <p>For Amazon EC2 APIs, see the <a href=\"https://docs.aws.amazon.com/AWSEC2/latest/APIReference/Welcome.html\">Amazon EC2 API\n                Reference</a>.</p>",
         "smithy.api#title": "AWS EC2 Instance Connect",
         "smithy.rules#endpointRuleSet": {
           "version": "1.0",
@@ -796,7 +796,7 @@
           "min": 1,
           "max": 32
         },
-        "smithy.api#pattern": "^[A-Za-z_][A-Za-z0-9\\@\\._-]{0,30}[A-Za-z0-9\\$_-]?$"
+        "smithy.api#pattern": "^(^[A-Za-z_][A-Za-z0-9\\@\\._-]{0,30}[A-Za-z0-9\\$_-]?$)|(^(?=.{2,32}$)[0-9]{1,32}[A-Za-z\\@\\._-][A-Za-z0-9\\@\\._-]*[A-Za-z0-9\\$_-]?$)$"
       }
     },
     "com.amazonaws.ec2instanceconnect#InvalidArgsException": {
@@ -971,6 +971,9 @@
         {
           "target": "com.amazonaws.ec2instanceconnect#SerialConsoleSessionUnavailableException"
         },
+        {
+          "target": "com.amazonaws.ec2instanceconnect#SerialConsoleSessionUnsupportedException"
+        },
         {
           "target": "com.amazonaws.ec2instanceconnect#ServiceException"
         },
@@ -1083,6 +1086,23 @@
         "smithy.api#httpError": 500
       }
     },
+    "com.amazonaws.ec2instanceconnect#SerialConsoleSessionUnsupportedException": {
+      "type": "structure",
+      "members": {
+        "Message": {
+          "target": "com.amazonaws.ec2instanceconnect#String"
+        }
+      },
+      "traits": {
+        "aws.protocols#awsQueryError": {
+          "code": "SerialConsoleSessionUnsupported",
+          "httpResponseCode": 400
+        },
+        "smithy.api#documentation": "<p>Your instance's BIOS version is unsupported for serial console connection. Reboot your instance to update its BIOS, and then try again to connect.</p>",
+        "smithy.api#error": "client",
+        "smithy.api#httpError": 400
+      }
+    },
     "com.amazonaws.ec2instanceconnect#SerialPort": {
       "type": "integer",
       "traits": {