diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5161f2f41..fd44c4bea 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -26,6 +26,7 @@
 * builder/amazon: Fix single `tag` interpolation to allow for templating engine
     usage. [GH-10224]
 * builder/yandex: Fixed using cloud config when using IPv6 [GH-10297]
+* post-processort/yandex-export: added check of service account id
 
 ## 1.6.5 (October 30, 2020)
 
diff --git a/builder/qemu/step_create_disk.go b/builder/qemu/step_create_disk.go
index 03de4fe7e..8a0c8eb51 100644
--- a/builder/qemu/step_create_disk.go
+++ b/builder/qemu/step_create_disk.go
@@ -32,12 +32,11 @@ func (s *stepCreateDisk) Run(ctx context.Context, state multistep.StateBag) mult
 		return multistep.ActionContinue
 	}
 
-	var diskFullPaths, diskSizes []string
-
 	ui.Say("Creating required virtual machine disks")
 	// The 'main' or 'default' disk
-	diskFullPaths = append(diskFullPaths, filepath.Join(s.OutputDir, name))
-	diskSizes = append(diskSizes, s.DiskSize)
+	diskFullPaths := []string{filepath.Join(s.OutputDir, name)}
+	diskSizes := []string{s.DiskSize}
+
 	// Additional disks
 	if len(s.AdditionalDiskSize) > 0 {
 		for i, diskSize := range s.AdditionalDiskSize {
diff --git a/builder/qemu/step_run.go b/builder/qemu/step_run.go
index ab2b36886..873b79256 100644
--- a/builder/qemu/step_run.go
+++ b/builder/qemu/step_run.go
@@ -216,8 +216,10 @@ func (s *stepRun) getDeviceAndDriveArgs(config *Config, state multistep.StateBag
 			drivesToAttach = append(drivesToAttach, imgPath)
 		}
 
-		diskFullPaths := state.Get("qemu_disk_paths").([]string)
-		drivesToAttach = append(drivesToAttach, diskFullPaths...)
+		if v, ok := state.GetOk("qemu_disk_paths"); ok {
+			diskFullPaths := v.([]string)
+			drivesToAttach = append(drivesToAttach, diskFullPaths...)
+		}
 
 		for i, drivePath := range drivesToAttach {
 			driveArgumentString := fmt.Sprintf("file=%s,if=%s,cache=%s,discard=%s,format=%s", drivePath, config.DiskInterface, config.DiskCache, config.DiskDiscard, config.Format)
@@ -284,7 +286,9 @@ func (s *stepRun) applyUserOverrides(defaultArgs map[string]interface{}, config
 
 		commHostPort := 0
 		if config.CommConfig.Comm.Type != "none" {
-			commHostPort = state.Get("commHostPort").(int)
+			if v, ok := state.GetOk("commHostPort"); ok {
+				commHostPort = v.(int)
+			}
 		}
 		httpIp := state.Get("http_ip").(string)
 		httpPort := state.Get("http_port").(int)
diff --git a/builder/virtualbox/common/guest_additions_config.go b/builder/virtualbox/common/guest_additions_config.go
index 673f4a3d1..5e8d430ba 100644
--- a/builder/virtualbox/common/guest_additions_config.go
+++ b/builder/virtualbox/common/guest_additions_config.go
@@ -83,9 +83,9 @@ func (c *GuestAdditionsConfig) Prepare(communicatorType string) []error {
 			fmt.Errorf("guest_additions_mode is invalid. Must be one of: %v", validModes))
 	}
 
-	if communicatorType == "none" && c.GuestAdditionsMode != "disable" {
-		errs = append(errs, fmt.Errorf("guest_additions_mode has to be "+
-			"'disable' when communicator = 'none'."))
+	if communicatorType == "none" && c.GuestAdditionsMode == "upload" {
+		errs = append(errs, fmt.Errorf("communicator must not be 'none' "+
+			"when guest_additions_mode = 'upload'."))
 	}
 
 	return errs
diff --git a/command/test-fixtures/validate/build.pkr.hcl b/command/test-fixtures/validate/build.pkr.hcl
index 416189e5a..b70cd535f 100644
--- a/command/test-fixtures/validate/build.pkr.hcl
+++ b/command/test-fixtures/validate/build.pkr.hcl
@@ -1,3 +1,7 @@
+packer {
+  required_version = ">= v1.0.0"
+}
+
 source "file" "chocolate" {
   target = "chocolate.txt"
   content = "chocolate"
diff --git a/command/test-fixtures/validate/invalid_packer_block.pkr.hcl b/command/test-fixtures/validate/invalid_packer_block.pkr.hcl
new file mode 100644
index 000000000..6388be9fd
--- /dev/null
+++ b/command/test-fixtures/validate/invalid_packer_block.pkr.hcl
@@ -0,0 +1,3 @@
+packer {
+  version = ">= v1.0.0"
+}
diff --git a/command/validate_test.go b/command/validate_test.go
index f8884cd18..ede32c1a3 100644
--- a/command/validate_test.go
+++ b/command/validate_test.go
@@ -26,6 +26,9 @@ func TestValidateCommand(t *testing.T) {
 
 		// wrong version field
 		{path: filepath.Join(testFixture("version_req", "wrong_field_name")), exitCode: 1},
+
+		// wrong packer block
+		{path: filepath.Join(testFixture("validate", "invalid_packer_block.pkr.hcl")), exitCode: 1},
 	}
 
 	for _, tc := range tt {
diff --git a/post-processor/yandex-export/post-processor.go b/post-processor/yandex-export/post-processor.go
index 8c48da450..e10deed7c 100644
--- a/post-processor/yandex-export/post-processor.go
+++ b/post-processor/yandex-export/post-processor.go
@@ -21,6 +21,8 @@ import (
 	"github.com/hashicorp/packer/packer-plugin-sdk/template/config"
 	"github.com/hashicorp/packer/packer-plugin-sdk/template/interpolate"
 	"github.com/hashicorp/packer/post-processor/artifice"
+	"github.com/yandex-cloud/go-genproto/yandex/cloud/iam/v1"
+	ycsdk "github.com/yandex-cloud/go-sdk"
 )
 
 const defaultStorageEndpoint = "storage.yandexcloud.net"
@@ -196,6 +198,11 @@ func (p *PostProcessor) PostProcess(ctx context.Context, ui packer.Ui, artifact
 		return nil, false, false, err
 	}
 
+	ui.Say(fmt.Sprintf("Validating service_account_id: '%s'...", yandexConfig.ServiceAccountID))
+	if err := validateServiceAccount(ctx, driver.SDK(), yandexConfig.ServiceAccountID); err != nil {
+		return nil, false, false, err
+	}
+
 	// Set up the state.
 	state := new(multistep.BasicStateBag)
 	state.Put("config", &yandexConfig)
@@ -259,3 +266,10 @@ func formUrls(paths []string) []string {
 	}
 	return result
 }
+
+func validateServiceAccount(ctx context.Context, ycsdk *ycsdk.SDK, serviceAccountID string) error {
+	_, err := ycsdk.IAM().ServiceAccount().Get(ctx, &iam.GetServiceAccountRequest{
+		ServiceAccountId: serviceAccountID,
+	})
+	return err
+}
diff --git a/post-processor/yandex-export/script.go b/post-processor/yandex-export/script.go
index d12883e08..b3d6b010a 100644
--- a/post-processor/yandex-export/script.go
+++ b/post-processor/yandex-export/script.go
@@ -110,8 +110,23 @@ if ! yc compute instance attach-disk ${INSTANCE_ID} --disk-name ${DISKNAME} --de
   Exit 1
 fi
 
+DISK_LINK="/dev/disk/by-id/virtio-doexport"
+echo "Waiting for disk..."
+for attempt in 1 2 3; do
+  sleep 3
+  /sbin/udevadm trigger
+  if [ -L "${DISK_LINK}" ]; then
+    break
+  fi
+  echo "Attempt ${attempt}"
+  if [ ${attempt} -eq 3 ]; then
+    echo "Symlink ${DISK_LINK} not found"
+    Exit 1
+  fi
+done
+
 echo "Dumping disk..."
-if ! qemu-img convert -O qcow2 -o cluster_size=2M /dev/disk/by-id/virtio-doexport disk.qcow2 ; then
+if ! qemu-img convert -O qcow2 -o cluster_size=2M "${DISK_LINK}" disk.qcow2 ; then
   echo "Failed to dump disk to qcow2 image."
   Exit 1
 fi
diff --git a/website/pages/docs/builders/vmware/vsphere-clone.mdx b/website/pages/docs/builders/vmware/vsphere-clone.mdx
index a9b68e4be..c12f999cf 100644
--- a/website/pages/docs/builders/vmware/vsphere-clone.mdx
+++ b/website/pages/docs/builders/vmware/vsphere-clone.mdx
@@ -141,7 +141,9 @@ can be done via environment variable:
           "network_interface": {
             "ipv4_address": "10.0.0.10",
             "ipv4_netmask": "24"
-          }
+          },
+          "ipv4_gateway": "10.0.0.1",
+          "dns_server_list": ["10.0.0.18"]
  }
 ```
 
@@ -159,6 +161,9 @@ can be done via environment variable:
            ipv4_address = "10.0.0.10"
            ipv4_netmask = "24"
          }
+
+         ipv4_gateway = 10.0.0.1
+         dns_server_list = ["10.0.0.18"]
    }
 ```
 
diff --git a/website/pages/docs/builders/vmware/vsphere-iso.mdx b/website/pages/docs/builders/vmware/vsphere-iso.mdx
index a6b06b6ec..f27bee15e 100644
--- a/website/pages/docs/builders/vmware/vsphere-iso.mdx
+++ b/website/pages/docs/builders/vmware/vsphere-iso.mdx
@@ -288,6 +288,8 @@ Minimal example of usage to import a OVF template:
 
 @include 'helper/communicator/SSH-not-required.mdx'
 
+@include 'helper/communicator/SSH-Private-Key-File-not-required.mdx'
+
 #### Optional WinRM fields:
 
 @include 'helper/communicator/WinRM-not-required.mdx'
diff --git a/website/pages/docs/from-1.5/blocks/packer.mdx b/website/pages/docs/from-1.5/blocks/packer.mdx
index 4b0e5b5c4..85d1cc114 100644
--- a/website/pages/docs/from-1.5/blocks/packer.mdx
+++ b/website/pages/docs/from-1.5/blocks/packer.mdx
@@ -11,6 +11,8 @@ description: |-
 
 `@include 'from-1.5/beta-hcl2-note.mdx'`
 
+-> **Note:** The Packer block is only available in Packer v1.6.5 and later.
+
 The `packer` configuration block type is used to configure some
 behaviors of Packer itself, such as the minimum required Packer version needed to 
 apply your configuration.