diff --git a/CHANGELOG/CHANGELOG-1.6.md b/CHANGELOG/CHANGELOG-1.6.md
index 6ebf8dfab..344b0ad35 100644
--- a/CHANGELOG/CHANGELOG-1.6.md
+++ b/CHANGELOG/CHANGELOG-1.6.md
@@ -1,6 +1,22 @@
 
 <hr>
 
+## [v1.6.4](https://github.com/aws/aws-k8s-tester/releases/tag/v1.6.4) (2021-10-13)
+
+See [code changes](https://github.com/aws/aws-k8s-tester/compare/v1.6.3...v1.6.4).
+
+### `eksconfig`
+
+- Support [Windows node group](https://github.com/aws/aws-k8s-tester/pull/241).
+
+### Go
+
+- Compile with [*Go 1.17.2*](https://golang.org/doc/devel/release.html#go1.17).
+
+
+<hr>
+
+
 ## [v1.6.3](https://github.com/aws/aws-k8s-tester/releases/tag/v1.6.3) (2021-10-06)
 
 See [code changes](https://github.com/aws/aws-k8s-tester/compare/v1.6.2...v1.6.3).
diff --git a/ec2config/config.go b/ec2config/config.go
index 8bb0a2256..beb1e5a83 100644
--- a/ec2config/config.go
+++ b/ec2config/config.go
@@ -31,6 +31,9 @@ const (
 	// AMITypeAL2X8664GPU is the AMI type for Amazon Linux 2 AMI with GPU.
 	AMITypeAL2X8664GPU = "AL2_x86_64_GPU"
 
+	// AMITypeOther is defined for all other AMI types.
+	AMITypeOther = "OTHER"
+
 	AMITypeWindowsServerCore2019X8664 = "WINDOWS_SERVER_CORE_2019_x86_64"
 
 	// DefaultNodeInstanceTypeCPUARM is the default EC2 instance type for CPU worker node.
diff --git a/ec2config/validate-defaults.go b/ec2config/validate-defaults.go
index d534a7ba3..049984b0b 100644
--- a/ec2config/validate-defaults.go
+++ b/ec2config/validate-defaults.go
@@ -349,6 +349,7 @@ func (cfg *Config) validateASGs() error {
 			if cur.RemoteAccessUserName != "ec2-user" {
 				return fmt.Errorf("AMIType %q but unexpected RemoteAccessUserName %q", cur.AMIType, cur.RemoteAccessUserName)
 			}
+		case AMITypeOther:
 		default:
 			return fmt.Errorf("unknown ASGs[%q].AMIType %q", k, cur.AMIType)
 		}
@@ -370,6 +371,7 @@ func (cfg *Config) validateASGs() error {
 			if cur.InstanceType == "" {
 				cur.InstanceType = DefaultNodeInstanceTypeGPU
 			}
+		case AMITypeOther:
 		default:
 			return fmt.Errorf("unknown ASGs[%q].AMIType %q", k, cur.AMIType)
 		}