diff --git a/common_arm/Makefile.hal b/common_arm/Makefile.hal
index 3aec0cc3b..429fc1717 100644
--- a/common_arm/Makefile.hal
+++ b/common_arm/Makefile.hal
@@ -98,6 +98,7 @@ endef
 PLTNAME = Unknown Platform
 PLATFORM_FPGA = fpga-undefined
 
+PLATFORM_DEFS =
 ifeq ($(PLATFORM),PM3RDV4)
     # FPGA bitstream files, the order doesn't matter anymore
     FPGA_BITSTREAMS = fpga_pm3_hf.bit