diff --git a/docs/platform-aws.md b/docs/platform-aws.md
index 0377f8db4..e4b3d992d 100644
--- a/docs/platform-aws.md
+++ b/docs/platform-aws.md
@@ -27,6 +27,9 @@ $ linuxkit build -format aws examples/aws.yml
 
 ## Push image
 
+Before you do this you need to create a `vmimport` service role as explained in
+[the VM import documentation](http://docs.aws.amazon.com/vm-import/latest/userguide/vmimport-image-import.html).
+
 Do `linuxkit push aws -bucket bucketname aws.raw` to upload it to the
 specified bucket, and create a bootable image from the stored image.
 
diff --git a/src/cmd/linuxkit/push_aws.go b/src/cmd/linuxkit/push_aws.go
index 18aa93689..3b5fe06ef 100644
--- a/src/cmd/linuxkit/push_aws.go
+++ b/src/cmd/linuxkit/push_aws.go
@@ -48,6 +48,9 @@ func pushAWS(args []string) {
 	timeout := getIntValue(timeoutVar, *timeoutFlag, 600)
 	bucket := getStringValue(bucketVar, *bucketFlag, "")
 	name := getStringValue(nameVar, *nameFlag, "")
+	if *sriovNetFlag == "" {
+		sriovNetFlag = nil
+	}
 
 	sess := session.Must(session.NewSession())
 	storage := s3.New(sess)