diff --git a/ports/stm32/stm32.mk b/ports/stm32/stm32.mk
index b9f70db73e..718fa8cf06 100644
--- a/ports/stm32/stm32.mk
+++ b/ports/stm32/stm32.mk
@@ -44,14 +44,14 @@ ifneq ($(BUILDING_MBOOT),1)
 SUPPORTS_HARDWARE_FP_SINGLE = 0
 SUPPORTS_HARDWARE_FP_DOUBLE = 0
 ifeq ($(CMSIS_MCU),$(filter $(CMSIS_MCU),STM32F765xx STM32F767xx STM32F769xx STM32H743xx STM32H747xx STM32H750xx STM32H7A3xx STM32H7A3xxQ STM32H7B3xx STM32H7B3xxQ))
-CFLAGS_CORTEX_M += -mfpu=fpv5-d16 -mfloat-abi=hard
+CFLAGS_CORTEX_M += -mfpu=fpv5-d16 -mfloat-abi=hard -mfp16-format=ieee
 SUPPORTS_HARDWARE_FP_SINGLE = 1
 SUPPORTS_HARDWARE_FP_DOUBLE = 1
 else
 ifeq ($(MCU_SERIES),$(filter $(MCU_SERIES),f0 g0 l0 l1 wl))
 CFLAGS_CORTEX_M += -msoft-float
 else
-CFLAGS_CORTEX_M += -mfpu=fpv4-sp-d16 -mfloat-abi=hard
+CFLAGS_CORTEX_M += -mfpu=fpv4-sp-d16 -mfloat-abi=hard -mfp16-format=ieee
 SUPPORTS_HARDWARE_FP_SINGLE = 1
 endif
 endif