diff --git a/blackfin_config.mk b/blackfin_config.mk
index f71a31370ec..beb9498e77f 100644
--- a/blackfin_config.mk
+++ b/blackfin_config.mk
@@ -21,4 +21,5 @@
 # MA 02111-1307 USA
 #
 
-PLATFORM_CPPFLAGS += -DCONFIG_BLACKFIN -D__BLACKFIN__
+PLATFORM_RELFLAGS += -ffixed-P5
+PLATFORM_CPPFLAGS += -DCONFIG_BLACKFIN
diff --git a/cpu/bf533/config.mk b/cpu/bf533/config.mk
index 6a713c3f51f..2caa3cc7d36 100644
--- a/cpu/bf533/config.mk
+++ b/cpu/bf533/config.mk
@@ -24,4 +24,4 @@
 # MA 02110-1301 USA
 #
 
-PLATFORM_RELFLAGS += -mcpu=bf533 -ffixed-P5
+PLATFORM_RELFLAGS += -mcpu=bf533
diff --git a/cpu/bf537/config.mk b/cpu/bf537/config.mk
index 8a35789f13c..fbbe75dede7 100644
--- a/cpu/bf537/config.mk
+++ b/cpu/bf537/config.mk
@@ -24,4 +24,4 @@
 # MA 02110-1301 USA
 #
 
-PLATFORM_RELFLAGS += -mcpu=bf537 -ffixed-P5
+PLATFORM_RELFLAGS += -mcpu=bf537
diff --git a/cpu/bf561/config.mk b/cpu/bf561/config.mk
index f4dc04bfc92..3628a026b0a 100644
--- a/cpu/bf561/config.mk
+++ b/cpu/bf561/config.mk
@@ -24,4 +24,4 @@
 # MA 02110-1301 USA
 #
 
-PLATFORM_RELFLAGS += -mcpu=bf561 -ffixed-P5
+PLATFORM_RELFLAGS += -mcpu=bf561