diff --git a/builtin/providers/aws/resource_aws_launch_configuration.go b/builtin/providers/aws/resource_aws_launch_configuration.go
index 8a4ffee6b..a232e6bb3 100644
--- a/builtin/providers/aws/resource_aws_launch_configuration.go
+++ b/builtin/providers/aws/resource_aws_launch_configuration.go
@@ -211,13 +211,6 @@ func resourceAwsLaunchConfiguration() *schema.Resource {
 						},
 					},
 				},
-				Set: func(v interface{}) int {
-					var buf bytes.Buffer
-					m := v.(map[string]interface{})
-					buf.WriteString(fmt.Sprintf("%s-", m["device_name"].(string)))
-					buf.WriteString(fmt.Sprintf("%s-", m["snapshot_id"].(string)))
-					return hashcode.String(buf.String())
-				},
 			},
 
 			"ephemeral_block_device": {
diff --git a/builtin/providers/aws/resource_aws_launch_configuration_test.go b/builtin/providers/aws/resource_aws_launch_configuration_test.go
index 8c1bde73a..c0e63de7b 100644
--- a/builtin/providers/aws/resource_aws_launch_configuration_test.go
+++ b/builtin/providers/aws/resource_aws_launch_configuration_test.go
@@ -198,7 +198,6 @@ func TestAccAWSLaunchConfiguration_withEncryption(t *testing.T) {
 				Config: testAccAWSLaunchConfigurationWithEncryption,
 				Check: resource.ComposeTestCheckFunc(
 					testAccCheckAWSLaunchConfigurationExists("aws_launch_configuration.baz", &conf),
-
 					testAccCheckAWSLaunchConfigurationWithEncryption(&conf),
 				),
 			},
@@ -206,6 +205,34 @@ func TestAccAWSLaunchConfiguration_withEncryption(t *testing.T) {
 	})
 }
 
+func TestAccAWSLaunchConfiguration_updateEbsBlockDevices(t *testing.T) {
+	var conf autoscaling.LaunchConfiguration
+
+	resource.Test(t, resource.TestCase{
+		PreCheck:     func() { testAccPreCheck(t) },
+		Providers:    testAccProviders,
+		CheckDestroy: testAccCheckAWSLaunchConfigurationDestroy,
+		Steps: []resource.TestStep{
+			{
+				Config: testAccAWSLaunchConfigurationWithEncryption,
+				Check: resource.ComposeTestCheckFunc(
+					testAccCheckAWSLaunchConfigurationExists("aws_launch_configuration.baz", &conf),
+					resource.TestCheckResourceAttr(
+						"aws_launch_configuration.baz", "ebs_block_device.2764618555.volume_size", "9"),
+				),
+			},
+			{
+				Config: testAccAWSLaunchConfigurationWithEncryptionUpdated,
+				Check: resource.ComposeTestCheckFunc(
+					testAccCheckAWSLaunchConfigurationExists("aws_launch_configuration.baz", &conf),
+					resource.TestCheckResourceAttr(
+						"aws_launch_configuration.baz", "ebs_block_device.3859927736.volume_size", "10"),
+				),
+			},
+		},
+	})
+}
+
 func testAccCheckAWSLaunchConfigurationGeneratedNamePrefix(
 	resource, prefix string) resource.TestCheckFunc {
 	return func(s *terraform.State) error {
@@ -444,6 +471,25 @@ resource "aws_launch_configuration" "baz" {
 	}
 }
 `
+
+const testAccAWSLaunchConfigurationWithEncryptionUpdated = `
+resource "aws_launch_configuration" "baz" {
+   image_id = "ami-5189a661"
+   instance_type = "t2.micro"
+   associate_public_ip_address = false
+
+   	root_block_device {
+   		volume_type = "gp2"
+		volume_size = 11
+	}
+	ebs_block_device {
+		device_name = "/dev/sdb"
+		volume_size = 10
+		encrypted = true
+	}
+}
+`
+
 const testAccAWSLaunchConfigurationConfig_withVpcClassicLink = `
 resource "aws_vpc" "foo" {
    cidr_block = "10.0.0.0/16"