diff --git a/conf/Makefile.arm-linux b/conf/Makefile.arm-linux
index 3efce866b2..9fef12bc6c 100644
--- a/conf/Makefile.arm-linux
+++ b/conf/Makefile.arm-linux
@@ -41,6 +41,9 @@ endif
 
 ARCH_CFLAGS ?= -mtune=cortex-a8 -march=armv7-a
 
+# with armv7, unaligned data can still be read
+CFLAGS += -DPPRZLINK_UNALIGNED_ACCESS=1
+
 # add ARM specifc flags to CFLAGS, LDFLAGS
 CFLAGS += $(FLOAT_ABI) $(ARCH_CFLAGS)
 LDFLAGS += $(FLOAT_ABI)
diff --git a/conf/Makefile.lpc21 b/conf/Makefile.lpc21
index e461cd670b..375cf1f2bd 100644
--- a/conf/Makefile.lpc21
+++ b/conf/Makefile.lpc21
@@ -104,6 +104,9 @@ CFLAGS += $($(TARGET).CFLAGS) $(USER_CFLAGS)
 # on old lpc, avoid using double precision in some geodetic functions
 CFLAGS += -DUSE_SINGLE_PRECISION_LLA_ECEF
 
+# LPC21 doesn't support unaligned data access
+CFLAGS += -DPPRZLINK_UNALIGNED_ACCESS=0
+
 # Assembler flags.
 ASFLAGS = -Wa,-adhlns=$(OBJDIR)/$(notdir $(<:.S=.lst))
 
diff --git a/conf/Makefile.nps b/conf/Makefile.nps
index 675db2360e..675b56d142 100644
--- a/conf/Makefile.nps
+++ b/conf/Makefile.nps
@@ -52,6 +52,9 @@ CXXFLAGS += $(shell pkg-config --cflags-only-I ivy-glib)
 
 LDFLAGS	+= $($(TARGET).LDFLAGS) -pthread
 
+# x86/64 and armv7 allow unaligned access
+CFLAGS += -DPPRZLINK_UNALIGNED_ACCESS=1
+
 #
 # General rules
 #
diff --git a/conf/Makefile.stm32 b/conf/Makefile.stm32
index 2d41a9c041..a51adf0334 100644
--- a/conf/Makefile.stm32
+++ b/conf/Makefile.stm32
@@ -115,6 +115,9 @@ else
 CFLAGS += -DSTM32F1
 endif
 
+# with cortex-m3 and m4 unaligned data can still be read
+CFLAGS += -DPPRZLINK_UNALIGNED_ACCESS=1
+
 CFLAGS += $($(TARGET).CFLAGS)
 
 AFLAGS  = -ahls -mapcs-32
diff --git a/sw/airborne/subsystems/datalink/datalink.h b/sw/airborne/subsystems/datalink/datalink.h
index 4c21f3fd74..8d4a53c456 100644
--- a/sw/airborne/subsystems/datalink/datalink.h
+++ b/sw/airborne/subsystems/datalink/datalink.h
@@ -33,12 +33,6 @@
 #define EXTERN extern
 #endif
 
-#ifdef __IEEE_BIG_ENDIAN /* From machine/ieeefp.h */
-#define Swap32IfBigEndian(_u) { _u = (_u << 32) | (_u >> 32); }
-#else
-#define Swap32IfBigEndian(_) {}
-#endif
-
 #include "std.h"
 #include "pprzlink/dl_protocol.h"
 
diff --git a/sw/ext/pprzlink b/sw/ext/pprzlink
index 6efd540406..1f3c7cd218 160000
--- a/sw/ext/pprzlink
+++ b/sw/ext/pprzlink
@@ -1 +1 @@
-Subproject commit 6efd540406cb5a2fdc6b27cc5befaa43bf54a4e6
+Subproject commit 1f3c7cd2186ec019d46c73dc2ed73a8714705ba5