diff --git a/efi/Makefile b/efi/Makefile
index d3788d90..869edfef 100644
--- a/efi/Makefile
+++ b/efi/Makefile
@@ -17,15 +17,15 @@ include $(MAKEDIR)/efi.mk
 # Upstream gnu-efi has old-style function definitions.
 CFLAGS += -Wno-strict-prototypes
 
-CORE_CSRC := $(wildcard $(core)/*.c $(core)/*/*.c $(core)/*/*/*.c)
+CORE_CSRC := $(sort $(wildcard $(core)/*.c $(core)/*/*.c $(core)/*/*/*.c))
 CORE_COBJ := $(subst $(core),$(OBJ)/../core,$(patsubst %.c,%.o,$(CORE_CSRC)))
 
 # We don't want to include any of the networking stack or the thread
 # code since it will be implemented completely differently for EFI.
-FILTERED_OBJS:= $(subst $(core),$(OBJ)/../core,$(patsubst %.c,%.o, \
+FILTERED_OBJS:= $(sort $(subst $(core),$(OBJ)/../core,$(patsubst %.c,%.o, \
 	$(wildcard $(core)/legacynet/*.c) \
 	$(wildcard $(core)/fs/pxe/*.c) \
-	$(wildcard $(core)/thread/*.c)))
+	$(wildcard $(core)/thread/*.c))))
 
 # Don't include unit tests
 FILTERED_OBJS += $(subst $(core),$(OBJ)/../core, \
@@ -44,7 +44,7 @@ CORE_OBJS += $(addprefix $(OBJ)/../core/, \
 LIB_OBJS = $(addprefix $(objdir)/com32/lib/,$(CORELIBOBJS)) \
 	$(LIBEFI)
 
-CSRC = $(wildcard $(SRC)/*.c)
+CSRC = $(sort $(wildcard $(SRC)/*.c))
 OBJS = $(subst $(SRC)/,,$(filter-out %wrapper.o, $(patsubst %.c,%.o,$(CSRC))))
 
 OBJS += $(objdir)/core/codepage.o $(ARCH)/linux.o