diff --git a/Makefile.include b/Makefile.include
index b0e294b5e..7ca2a8d13 100644
--- a/Makefile.include
+++ b/Makefile.include
@@ -51,7 +51,7 @@ OBJECTDIR = obj_$(TARGET)
 
 LOWERCASE = -abcdefghijklmnopqrstuvwxyz
 UPPERCASE = _ABCDEFGHIJKLMNOPQRSTUVWXYZ
-TARGET_UPPERCASE := ${strip ${shell echo $(TARGET) | sed y!$(LOWERCASE)!$(UPPERCASE)!}}
+TARGET_UPPERCASE := ${strip ${shell echo $(TARGET) | sed 'y!$(LOWERCASE)!$(UPPERCASE)!'}}
 CFLAGS += -DCONTIKI=1 -DCONTIKI_TARGET_$(TARGET_UPPERCASE)=1
 
 include $(CONTIKI)/core/net/rime/Makefile.rime
@@ -64,7 +64,7 @@ LIBS    = memb.c mmem.c timer.c list.c etimer.c ctimer.c energest.c rtimer.c sti
 DEV     = nullradio.c
 NET     = netstack.c uip-debug.c packetbuf.c queuebuf.c packetqueue.c
 
-ifdef UIP_CONF_IPV6
+ifeq ($(UIP_CONF_IPV6),1)
   CFLAGS += -DUIP_CONF_IPV6=1
   UIP   = uip6.c tcpip.c psock.c uip-udp-packet.c uip-split.c \
           resolv.c tcpdump.c uiplib.c simple-udp.c
diff --git a/core/net/rime/Makefile.rime b/core/net/rime/Makefile.rime
index e45e0c391..c99faa3d5 100644
--- a/core/net/rime/Makefile.rime
+++ b/core/net/rime/Makefile.rime
@@ -1,4 +1,4 @@
-ifdef UIP_CONF_IPV6
+ifeq ($(UIP_CONF_IPV6),1)
 #RIME_UIP6      = rime-udp.c
 RIME_BASE      = rimeaddr.c timesynch.c rimestats.c
 else
diff --git a/platform/cc2530dk/Makefile.cc2530dk b/platform/cc2530dk/Makefile.cc2530dk
index 83bbffeb7..655679d66 100644
--- a/platform/cc2530dk/Makefile.cc2530dk
+++ b/platform/cc2530dk/Makefile.cc2530dk
@@ -19,7 +19,7 @@ CONTIKI_SOURCEFILES += $(CONTIKI_TARGET_SOURCEFILES)
 
 CLEAN += *.cc2530dk
 
-ifdef UIP_CONF_IPV6
+ifeq ($(UIP_CONF_IPV6),1)
   CONTIKI_TARGET_SOURCEFILES += viztool.c
 endif
 
diff --git a/platform/cooja/Makefile.cooja b/platform/cooja/Makefile.cooja
index d40bfb0a2..2e61093d4 100644
--- a/platform/cooja/Makefile.cooja
+++ b/platform/cooja/Makefile.cooja
@@ -73,7 +73,7 @@ CONTIKI_CPU=$(CONTIKI)/cpu/x86
 CFLAGSNO = $(EXTRA_CC_ARGS) -Wall -g -I/usr/local/include -DCLASSNAME=$(CLASSNAME)
 CFLAGS   += $(CFLAGSNO)
 
-ifdef UIP_CONF_IPV6
+ifeq ($(UIP_CONF_IPV6),1)
   CFLAGS += -DWITH_UIP6=1
 endif
 ifdef WITH_UIP
@@ -81,7 +81,7 @@ ifdef WITH_UIP
 endif
 
 ## Copied from Makefile.include, since Cooja overrides CFLAGS et al
-ifdef UIP_CONF_IPV6
+ifeq ($(UIP_CONF_IPV6),1)
   CFLAGS += -DUIP_CONF_IPV6=1
   ifneq ($(UIP_CONF_RPL),0)
     CFLAGS += -DUIP_CONF_IPV6_RPL=1
diff --git a/platform/econotag/Makefile.econotag b/platform/econotag/Makefile.econotag
index 95c93a56b..99f837501 100644
--- a/platform/econotag/Makefile.econotag
+++ b/platform/econotag/Makefile.econotag
@@ -14,7 +14,7 @@ CONTIKI_PLAT_DEFS =
 
 MCU=arm7tdmi-s
 
-ifdef UIP_CONF_IPV6
+ifeq ($(UIP_CONF_IPV6),1)
 CFLAGS += -DWITH_UIP6=1
 endif
 
diff --git a/platform/exp5438/Makefile.exp5438 b/platform/exp5438/Makefile.exp5438
index d22f18a4a..e2a1c3297 100644
--- a/platform/exp5438/Makefile.exp5438
+++ b/platform/exp5438/Makefile.exp5438
@@ -40,7 +40,7 @@ ifndef CONTIKI_TARGET_MAIN
 CONTIKI_TARGET_MAIN = contiki-exp5438-main.c
 endif
 
-ifdef UIP_CONF_IPV6
+ifeq ($(UIP_CONF_IPV6),1)
 CFLAGS += -DWITH_UIP6=1
 endif
 
diff --git a/platform/iris/Makefile.iris b/platform/iris/Makefile.iris
index d7ce508bb..1558857f5 100644
--- a/platform/iris/Makefile.iris
+++ b/platform/iris/Makefile.iris
@@ -51,7 +51,7 @@ ifneq ($(strip $(HAVE_PRGBOARD_FILE)), )
 endif 
 
 include $(CONTIKIAVR)/radio/Makefile.radio
-ifdef UIP_CONF_IPV6
+ifeq ($(UIP_CONF_IPV6),1)
 CFLAGS += -DWITH_UIP6=1
 endif
 
diff --git a/platform/mb851/Makefile.mb851 b/platform/mb851/Makefile.mb851
index 4b24b82b2..2c9c14da3 100644
--- a/platform/mb851/Makefile.mb851
+++ b/platform/mb851/Makefile.mb851
@@ -8,7 +8,7 @@ ifndef CONTIKI_TARGET_MAIN
 CONTIKI_TARGET_MAIN = contiki-main.c board-mb851.c
 endif
 
-ifdef UIP_CONF_IPV6
+ifeq ($(UIP_CONF_IPV6),1)
 CFLAGS += -DWITH_UIP6=1
 endif
 
diff --git a/platform/mbxxx/Makefile.mbxxx b/platform/mbxxx/Makefile.mbxxx
index 1a35c6d9a..f6aa436a2 100644
--- a/platform/mbxxx/Makefile.mbxxx
+++ b/platform/mbxxx/Makefile.mbxxx
@@ -7,7 +7,7 @@ ifndef CONTIKI_TARGET_MAIN
 CONTIKI_TARGET_MAIN = contiki-main.c led.c button.c board.c board-mbxxx.c
 endif
 
-ifdef UIP_CONF_IPV6
+ifeq ($(UIP_CONF_IPV6),1)
 CFLAGS += -DWITH_UIP6=1
 endif
 
diff --git a/platform/minimal-net/Makefile.minimal-net b/platform/minimal-net/Makefile.minimal-net
index 296d5684e..91dd1aaeb 100644
--- a/platform/minimal-net/Makefile.minimal-net
+++ b/platform/minimal-net/Makefile.minimal-net
@@ -16,7 +16,7 @@ CONTIKI_TARGET_SOURCEFILES += wpcap-drv.c wpcap.c
 else
 CONTIKI_TARGET_SOURCEFILES += tapdev-drv.c
 #math
-ifndef UIP_CONF_IPV6
+ifneq ($(UIP_CONF_IPV6),1)
 CONTIKI_TARGET_SOURCEFILES += tapdev.c
 else
 CONTIKI_TARGET_SOURCEFILES += tapdev6.c
diff --git a/platform/native/Makefile.native b/platform/native/Makefile.native
index 36368e266..60591c6a8 100644
--- a/platform/native/Makefile.native
+++ b/platform/native/Makefile.native
@@ -6,7 +6,7 @@ ifeq ($(HOST_OS),Darwin)
   AROPTS = rc
 endif
 
-ifdef UIP_CONF_IPV6
+ifeq ($(UIP_CONF_IPV6),1)
 CFLAGS += -DWITH_UIP6=1
 endif
 
@@ -23,7 +23,7 @@ TARGET_LIBFILES = /lib/w32api/libws2_32.a /lib/w32api/libiphlpapi.a
 else
 CONTIKI_TARGET_SOURCEFILES += tapdev-drv.c
 #math
-ifndef UIP_CONF_IPV6
+ifneq ($(UIP_CONF_IPV6),1)
 CONTIKI_TARGET_SOURCEFILES += tapdev.c
 else
 CONTIKI_TARGET_SOURCEFILES += tapdev6.c
diff --git a/platform/redbee-dev/Makefile.redbee-dev b/platform/redbee-dev/Makefile.redbee-dev
index 04be24562..7c4f29230 100644
--- a/platform/redbee-dev/Makefile.redbee-dev
+++ b/platform/redbee-dev/Makefile.redbee-dev
@@ -13,7 +13,7 @@ CONTIKI_PLAT_DEFS =
 
 MCU=arm7tdmi-s
 
-ifdef UIP_CONF_IPV6
+ifeq ($(UIP_CONF_IPV6),1)
 CFLAGS += -DWITH_UIP6=1
 endif
 
diff --git a/platform/redbee-econotag/Makefile.redbee-econotag b/platform/redbee-econotag/Makefile.redbee-econotag
index 61d809d1a..4825b508b 100644
--- a/platform/redbee-econotag/Makefile.redbee-econotag
+++ b/platform/redbee-econotag/Makefile.redbee-econotag
@@ -24,7 +24,7 @@ CONTIKI_PLAT_DEFS =
 
 MCU=arm7tdmi-s
 
-ifdef UIP_CONF_IPV6
+ifeq ($(UIP_CONF_IPV6),1)
 CFLAGS += -DWITH_UIP6=1
 endif
 
diff --git a/platform/seedeye/Makefile.seedeye b/platform/seedeye/Makefile.seedeye
index 922d8868f..988e54a07 100644
--- a/platform/seedeye/Makefile.seedeye
+++ b/platform/seedeye/Makefile.seedeye
@@ -6,7 +6,7 @@ ifdef SEEDEYE_ID
 CFLAGS += -DSEEDEYE_ID=${SEEDEYE_ID}
 endif
 
-ifdef UIP_CONF_IPV6
+ifeq ($(UIP_CONF_IPV6),1)
 CFLAGS += -DWITH_UIP6=1
 endif
 
diff --git a/platform/sensinode/Makefile.sensinode b/platform/sensinode/Makefile.sensinode
index a1ecf6af1..c74a70181 100644
--- a/platform/sensinode/Makefile.sensinode
+++ b/platform/sensinode/Makefile.sensinode
@@ -46,7 +46,7 @@ CONTIKI_SOURCEFILES += $(CONTIKI_TARGET_SOURCEFILES)
 
 CLEAN += *.sensinode
 
-ifdef UIP_CONF_IPV6
+ifeq ($(UIP_CONF_IPV6),1)
   ifeq ($(OFFSET_FIRMWARE),1)
     CFLAGS += -DDISCO_ENABLED=1
     CONTIKI_TARGET_SOURCEFILES += disco.c
diff --git a/platform/sky/Makefile.common b/platform/sky/Makefile.common
index 212f95554..64484e1da 100644
--- a/platform/sky/Makefile.common
+++ b/platform/sky/Makefile.common
@@ -10,7 +10,7 @@ ifndef CONTIKI_TARGET_MAIN
 CONTIKI_TARGET_MAIN = contiki-sky-main.c
 endif
 
-ifdef UIP_CONF_IPV6
+ifeq ($(UIP_CONF_IPV6),1)
 CFLAGS += -DWITH_UIP6=1
 endif
 
diff --git a/platform/wismote/Makefile.wismote b/platform/wismote/Makefile.wismote
index 71850bd59..a037ced0e 100644
--- a/platform/wismote/Makefile.wismote
+++ b/platform/wismote/Makefile.wismote
@@ -18,7 +18,7 @@ ifndef CONTIKI_TARGET_MAIN
 CONTIKI_TARGET_MAIN = contiki-wismote-main.c
 endif
 
-ifdef UIP_CONF_IPV6
+ifeq ($(UIP_CONF_IPV6),1)
 CFLAGS += -DWITH_UIP6=1
 endif
 
diff --git a/platform/z1/Makefile.common b/platform/z1/Makefile.common
index 72a1270d6..57536b3e2 100644
--- a/platform/z1/Makefile.common
+++ b/platform/z1/Makefile.common
@@ -24,7 +24,7 @@ ifndef CONTIKI_TARGET_MAIN
 CONTIKI_TARGET_MAIN = contiki-z1-main.c
 endif
 
-ifdef UIP_CONF_IPV6
+ifeq ($(UIP_CONF_IPV6),1)
 CFLAGS += -DWITH_UIP6=1
 endif