diff --git a/Config.mk b/Config.mk
index f9dce4549b..4d723eec1d 100644
--- a/Config.mk
+++ b/Config.mk
@@ -244,7 +244,7 @@ QEMU_TRADITIONAL_URL ?= git://xenbits.xen.org/qemu-xen-traditional.git
 SEABIOS_UPSTREAM_URL ?= git://xenbits.xen.org/seabios.git
 MINIOS_UPSTREAM_URL ?= git://xenbits.xen.org/mini-os.git
 endif
-OVMF_UPSTREAM_REVISION ?= e1999b264f1f9d7230edf2448f757c73da567832
+OVMF_UPSTREAM_REVISION ?= b37cfdd2807181aed2fee1e17bd7ec1190db266a
 QEMU_UPSTREAM_REVISION ?= master
 MINIOS_UPSTREAM_REVISION ?= 051b87bb9c19609976fb038f386920e1ce5454c5
 
diff --git a/tools/firmware/ovmf-makefile b/tools/firmware/ovmf-makefile
index 55f9992145..1f619a5189 100644
--- a/tools/firmware/ovmf-makefile
+++ b/tools/firmware/ovmf-makefile
@@ -17,8 +17,14 @@ all: build
 .PHONY: build
 build:
 	if test -e .git ; then $(GIT) submodule update --init --recursive ; fi
-	OvmfPkg/build.sh -a X64 -b $(TARGET) -n 4
-	cp Build/OvmfX64/$(TARGET)_GCC*/FV/OVMF.fd ovmf.bin
+	set -ex; \
+	if test -e OvmfPkg/OvmfXen.dsc; then \
+	  OvmfPkg/build.sh -a X64 -b $(TARGET) -p OvmfPkg/OvmfXen.dsc; \
+	  cp Build/OvmfXen/$(TARGET)_GCC*/FV/OVMF.fd ovmf.bin; \
+	else \
+	  OvmfPkg/build.sh -a X64 -b $(TARGET) -n 4; \
+	  cp Build/OvmfX64/$(TARGET)_GCC*/FV/OVMF.fd ovmf.bin; \
+	fi
 
 .PHONY: clean
 clean: