diff --git a/port/stm32-f4discovery-cc256x/cubemx-f4discovery-cc256x/Makefile b/port/stm32-f4discovery-cc256x/cubemx-f4discovery-cc256x/Makefile
index b00f479cb..0f891ca5c 100644
--- a/port/stm32-f4discovery-cc256x/cubemx-f4discovery-cc256x/Makefile
+++ b/port/stm32-f4discovery-cc256x/cubemx-f4discovery-cc256x/Makefile
@@ -207,7 +207,7 @@ CPU = -mcpu=cortex-m4
 FPU = -mfpu=fpv4-sp-d16
 
 # float-abi
-FLOAT-ABI = -mfloat-abi=hard
+FLOAT-ABI = -mfloat-abi=softfp
 
 # mcu
 MCU = $(CPU) -mthumb $(FPU) $(FLOAT-ABI)
@@ -249,6 +249,7 @@ C_INCLUDES += -I${BTSTACK_ROOT}/3rd-party/yxml
 C_INCLUDES += -I${BTSTACK_ROOT}/3rd-party/segger-rtt
 C_INCLUDES += -I${BTSTACK_ROOT}/platform/embedded
 C_INCLUDES += -I${BTSTACK_ROOT}/chipset/cc256x
+C_INCLUDES += -I../pdm
 C_INCLUDES += -I../src
 C_INCLUDES += -I../src/bsp
 C_INCLUDES += -I../eclipse-template/include
@@ -277,8 +278,8 @@ CFLAGS += -MMD -MP -MF"$(@:%.o=%.d)" -MT"$(@:%.o=%.d)"
 LDSCRIPT = STM32F407VGTx_FLASH.ld
 
 # libraries
-LIBS = -lc -lm -lnosys
-LIBDIR =
+LIBS = -lPDMFilter_CM4_GCC -lc -lm -lnosys 
+LIBDIR = -L../pdm
 LDFLAGS = $(MCU) -specs=nano.specs -T$(LDSCRIPT) $(LIBDIR) $(LIBS) -Wl,-Map=$(BUILD_DIR)/$(TARGET).map,--cref -Wl,--gc-sections
 
 # default action: build all