--- a/config/Config-images.in.orig	2019-05-28 14:40:45.246749741 +0200
+++ b/config/Config-images.in	2019-05-28 14:41:14.866378695 +0200
@@ -251,6 +251,13 @@
 		select TARGET_IMAGES_PAD
 		select PACKAGE_kmod-e1000
 
+	config VHDX_IMAGES
+		bool "Build Hyper-V image files (VHDX)"
+		depends on TARGET_x86
+		select GRUB_IMAGES
+		select TARGET_IMAGES_PAD
+		select PACKAGE_kmod-e1000
+
 	config TARGET_IMAGES_PAD
 		bool "Pad images to filesystem size (for JFFS2)"
 		depends on GRUB_IMAGES
--- a/target/linux/x86/image/Makefile	2019-05-28 14:35:00.895067331 +0200
+++ b/target/linux/x86/image/Makefile	2019-05-28 14:42:40.461306376 +0200
@@ -137,12 +137,21 @@
 ifneq ($(CONFIG_VMDK_IMAGES),)
   define Image/Build/vmdk
 	rm $(BIN_DIR)/$(IMG_PREFIX)-combined-$(1).vmdk || true
-	qemu-img convert -f raw -O vmdk \
+	qemu-img convert -f raw -O vmdk -o subformat=streamOptimized,adapter_type=lsilogic,compat6 \
 		$(BIN_DIR)/$(IMG_PREFIX)-combined-$(1).img \
 		$(BIN_DIR)/$(IMG_PREFIX)-combined-$(1).vmdk
   endef
 endif
 
+ifneq ($(CONFIG_HYPERV_IMAGES),)
+  define Image/Build/hyperv
+	rm $(BIN_DIR)/$(IMG_PREFIX)-combined-$(1).vhdx || true
+	qemu-img convert -f raw -O vhdx \
+		$(BIN_DIR)/$(IMG_PREFIX)-combined-$(1).img \
+		$(BIN_DIR)/$(IMG_PREFIX)-combined-$(1).vhdx
+  endef
+endif
+
 define Image/Build/gzip
 	gzip -f9n $(BIN_DIR)/$(IMG_PREFIX)-combined-$(1).img
 	gzip -f9n $(BIN_DIR)/$(IMG_PREFIX)-rootfs-$(1).img