diff --git a/Makefile b/Makefile
index 5d018d1..868a273 100644
--- a/Makefile
+++ b/Makefile
@@ -37,10 +37,40 @@ create_build_dir:
 	mkdir -p $(BUILDDIR)/uip
 	mkdir -p $(BUILDDIR)/httpd
 
-SRCS = rtlplayground.c rtl837x_flash.c rtl837x_leds.c rtl837x_phy.c rtl837x_port.c cmd_parser.c html_data.c rtl837x_igmp.c
-SRCS += rtl837x_stp.c rtl837x_pins.c dhcp.c machine.c cmd_editor.c rtl837x_bandwidth.c rtl837x_init.c syslog.c
-SRCS += uip/timer.c uip/uip.c uip/uip_arp.c uip/uiplib.c uip/uip-fw.c uip/uip-neighbor.c uip/uip-split.c udp_apps.c
-SRCS += httpd/httpd.c httpd/page_impl.c
+# Keep machine.c in first position to fail immediately on invalid $MACHINE value
+SRCS = \
+	machine.c \
+	cmd_editor.c \
+	cmd_parser.c \
+	dhcp.c \
+	html_data.c \
+	rtlplayground.c \
+	syslog.c \
+	udp_apps.c
+
+# RTL837x
+SRCS += \
+	rtl837x_bandwidth.c \
+	rtl837x_flash.c \
+	rtl837x_igmp.c \
+	rtl837x_init.c \
+	rtl837x_leds.c \
+	rtl837x_phy.c \
+	rtl837x_pins.c\
+	rtl837x_port.c \
+	rtl837x_stp.c
+SRCS += \
+	httpd/httpd.c \
+	httpd/page_impl.c
+SRCS += \
+	uip/timer.c \
+	uip/uip.c \
+	uip/uiplib.c \
+	uip/uip_arp.c \
+	uip/uip-fw.c \
+	uip/uip-neighbor.c \
+	uip/uip-split.c
+
 OBJS = ${SRCS:%.c=$(BUILDDIR)/%.rel}
 DEPS := ${SRCS:%.c=$(BUILDDIR)/%.d}
 HTML := $(shell find $(html) -name '*.js' -or -name '*.html' -or -name '*.svg')