diff --git a/tools/firmware/hvmloader/Makefile b/tools/firmware/hvmloader/Makefile
index b754220839..4f31c88161 100644
--- a/tools/firmware/hvmloader/Makefile
+++ b/tools/firmware/hvmloader/Makefile
@@ -60,8 +60,7 @@ ROMS += $(ROMBIOS_ROM) $(STDVGA_ROM) $(CIRRUSVGA_ROM)
 endif
 
 .PHONY: all
-all: acpi
-	$(MAKE) hvmloader
+all: hvmloader
 
 .PHONY: acpi
 acpi:
@@ -73,12 +72,18 @@ smbios.o: CFLAGS += -D__SMBIOS_DATE__="\"$(SMBIOS_REL_DATE)\""
 ACPI_PATH = ../../libacpi
 DSDT_FILES = dsdt_anycpu.c dsdt_15cpu.c dsdt_anycpu_qemu_xen.c
 ACPI_OBJS = $(patsubst %.c,%.o,$(DSDT_FILES)) build.o static_tables.o
-$(ACPI_OBJS): CFLAGS += -I. -DLIBACPI_STDUTILS=\"$(CURDIR)/util.h\"
+$(ACPI_OBJS): CFLAGS += -iquote . -DLIBACPI_STDUTILS=\"$(CURDIR)/util.h\"
 CFLAGS += -I$(ACPI_PATH)
 vpath build.c $(ACPI_PATH)
 vpath static_tables.c $(ACPI_PATH)
 OBJS += $(ACPI_OBJS)
 
+$(DSDT_FILES): acpi
+
+# Add DSDT_FILES as a prerequisite of "build.o" so that make will also
+# generate the "ssdt_*.h" headers needed by "build.o".
+build.o: $(DSDT_FILES)
+
 hvmloader: $(OBJS) hvmloader.lds
 	$(LD) $(LDFLAGS_DIRECT) -N -T hvmloader.lds -o $@ $(OBJS)
 
@@ -87,21 +92,21 @@ roms.inc: $(ROMS)
 
 ifneq ($(ROMBIOS_ROM),)
 	echo "#ifdef ROM_INCLUDE_ROMBIOS" >> $@.new
-	sh ../../misc/mkhex rombios $(ROMBIOS_ROM) >> $@.new
+	$(SHELL) $(XEN_ROOT)/tools/misc/mkhex rombios $(ROMBIOS_ROM) >> $@.new
 	echo "#endif" >> $@.new
 endif
 
 ifneq ($(STDVGA_ROM),)
 	echo "#ifdef ROM_INCLUDE_VGABIOS" >> $@.new
-	sh ../../misc/mkhex vgabios_stdvga $(STDVGA_ROM) >> $@.new
+	$(SHELL) $(XEN_ROOT)/tools/misc/mkhex vgabios_stdvga $(STDVGA_ROM) >> $@.new
 	echo "#endif" >> $@.new
 endif
 ifneq ($(CIRRUSVGA_ROM),)
 	echo "#ifdef ROM_INCLUDE_VGABIOS" >> $@.new
-	sh ../../misc/mkhex vgabios_cirrusvga $(CIRRUSVGA_ROM) >> $@.new
+	$(SHELL) $(XEN_ROOT)/tools/misc/mkhex vgabios_cirrusvga $(CIRRUSVGA_ROM) >> $@.new
 	echo "#endif" >> $@.new
 endif
-	mv $@.new $@
+	mv -f $@.new $@
 
 .PHONY: clean
 clean: