diff --git a/builder/hyperv/iso/builder.go b/builder/hyperv/iso/builder.go
index 155c51614..a364c3226 100644
--- a/builder/hyperv/iso/builder.go
+++ b/builder/hyperv/iso/builder.go
@@ -66,7 +66,7 @@ type Config struct {
 	DiskSize uint `mapstructure:"disk_size" required:"false"`
 	// The block size of the VHD to be created.
 	// Recommended disk block size for Linux hyper-v guests is 1 MiB. This
-	// defaults to "32 MiB".
+	// defaults to "32" MiB.
 	DiskBlockSize uint `mapstructure:"disk_block_size" required:"false"`
 	// The amount, in megabytes, of RAM to assign to the
 	// VM. By default, this is 1 GB.
diff --git a/common/iso_config_test.go b/common/iso_config_test.go
index b04e0933f..9ffe6fecf 100644
--- a/common/iso_config_test.go
+++ b/common/iso_config_test.go
@@ -164,7 +164,15 @@ func TestISOConfigPrepare_ISOUrl(t *testing.T) {
 	i.RawSingleISOUrl = ""
 	i.ISOChecksum = ""
 	i.ISOChecksumURL = ts.URL + "/basic.txt"
-	warns, err = i.Prepare(nil)
+	// ISOConfig.Prepare() returns a slice of errors
+	var errs []error
+	warns, errs = i.Prepare(nil)
+	if len(warns) > 0 {
+		t.Fatalf("expected no warnings, got:%v", warns)
+	}
+	if len(errs) < 1 || err[0] == nil {
+		t.Fatalf("expected a populated error slice, got: %v", errs)
+	}
 
 	// Test iso_url set
 	i = testISOConfig()
diff --git a/website/source/partials/builder/hyperv/iso/_Config-not-required.html.md b/website/source/partials/builder/hyperv/iso/_Config-not-required.html.md
index 380b21660..4bdde113c 100644
--- a/website/source/partials/builder/hyperv/iso/_Config-not-required.html.md
+++ b/website/source/partials/builder/hyperv/iso/_Config-not-required.html.md
@@ -5,7 +5,7 @@
     
 -   `disk_block_size` (uint) - The block size of the VHD to be created.
     Recommended disk block size for Linux hyper-v guests is 1 MiB. This
-    defaults to "32 MiB".
+    defaults to "32" MiB.
     
 -   `memory` (uint) - The amount, in megabytes, of RAM to assign to the
     VM. By default, this is 1 GB.