diff --git a/src/Makefile b/src/Makefile
index 474e8cfd..40906a8e 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -71,7 +71,7 @@ noargs : blib $(BIN)/NIC $(BIN)/gpxe.dsk $(BIN)/gpxe.iso $(BIN)/gpxe.usb $(BIN)/
 # If no architecture is specified in Config or on the command-line,
 # use that of the build machine.
 #
-ARCH		?= $(shell uname -m | sed -e s,i[3456789]86,i386,)
+ARCH		:= $(shell uname -m | sed -e s,i[3456789]86,i386,)
 
 # handle x86_64 like i386, but set -m32 option for 32bit code only
 ifeq ($(ARCH),x86_64)
@@ -98,7 +98,7 @@ LDFLAGS		+= $(EXTRA_LDFLAGS)
 
 # Embedded image, if present
 #
-EMBEDDED_IMAGE	?= /dev/null
+EMBEDDED_IMAGE	 = /dev/null
 
 ifneq ($(NO_WERROR),1)
 CFLAGS		+= -Werror
diff --git a/src/Makefile.housekeeping b/src/Makefile.housekeeping
index 69d8af6c..aafd7d71 100644
--- a/src/Makefile.housekeeping
+++ b/src/Makefile.housekeeping
@@ -58,16 +58,16 @@ ECHO_E_BIN_ECHO_TAB 	:= $(shell $(ECHO_E_BIN_ECHO) '\t')
 ECHO_E_BIN_ECHO_E_TAB 	:= $(shell $(ECHO_E_BIN_ECHO_E) '\t')
 
 ifeq ($(ECHO_E_ECHO_TAB),$(TAB))
-ECHO_E		?= $(ECHO_E_ECHO)
+ECHO_E		:= $(ECHO_E_ECHO)
 endif
 ifeq ($(ECHO_E_ECHO_E_TAB),$(TAB))
-ECHO_E		?= $(ECHO_E_ECHO_E)
+ECHO_E		:= $(ECHO_E_ECHO_E)
 endif
 ifeq ($(ECHO_E_BIN_ECHO_TAB),$(TAB))
-ECHO_E		?= $(ECHO_E_BIN_ECHO)
+ECHO_E		:= $(ECHO_E_BIN_ECHO)
 endif
 ifeq ($(ECHO_E_BIN_ECHO_E_TAB),$(TAB))
-ECHO_E		?= $(ECHO_E_BIN_ECHO_E)
+ECHO_E		:= $(ECHO_E_BIN_ECHO_E)
 endif
 
 .echocheck :