diff --git a/.github/workflows/build_iar.yml b/.github/workflows/build_iar.yml
index c948b5d8d..9c1bfa18a 100644
--- a/.github/workflows/build_iar.yml
+++ b/.github/workflows/build_iar.yml
@@ -33,6 +33,7 @@ jobs:
         - 'stm32f7'
         - 'stm32g4'
         - 'stm32h7'
+        - 'stm32l4'
     steps:
     - name: Clean workspace
       run: |
diff --git a/hw/bsp/stm32l4/boards/stm32l412nucleo/board.mk b/hw/bsp/stm32l4/boards/stm32l412nucleo/board.mk
index 841ee4948..854397fc8 100644
--- a/hw/bsp/stm32l4/boards/stm32l412nucleo/board.mk
+++ b/hw/bsp/stm32l4/boards/stm32l412nucleo/board.mk
@@ -1,10 +1,13 @@
 CFLAGS += \
   -DSTM32L412xx \
 
-# All source paths should be relative to the top level.
-LD_FILE = $(BOARD_PATH)/STM32L412KBUx_FLASH.ld
+# GCC
+GCC_SRC_S += $(ST_CMSIS)/Source/Templates/gcc/startup_stm32l412xx.s
+GCC_LD_FILE = $(BOARD_PATH)/STM32L412KBUx_FLASH.ld
 
-SRC_S += $(ST_CMSIS)/Source/Templates/gcc/startup_stm32l412xx.s
+# IAR
+IAR_SRC_S += $(ST_CMSIS)/Source/Templates/iar/startup_stm32l412xx.s
+IAR_LD_FILE = $(ST_CMSIS)/Source/Templates/iar/linker/stm32l412xx_flash.icf
 
 # For flash-jlink target
 JLINK_DEVICE = stm32l412kb
diff --git a/hw/bsp/stm32l4/boards/stm32l476disco/board.mk b/hw/bsp/stm32l4/boards/stm32l476disco/board.mk
index e7b8557a5..125f1f106 100644
--- a/hw/bsp/stm32l4/boards/stm32l476disco/board.mk
+++ b/hw/bsp/stm32l4/boards/stm32l476disco/board.mk
@@ -1,10 +1,13 @@
 CFLAGS += \
   -DSTM32L476xx \
 
-# All source paths should be relative to the top level.
-LD_FILE = $(BOARD_PATH)/STM32L476VGTx_FLASH.ld
+# GCC
+GCC_SRC_S += $(ST_CMSIS)/Source/Templates/gcc/startup_stm32l476xx.s
+GCC_LD_FILE = $(BOARD_PATH)/STM32L476VGTx_FLASH.ld
 
-SRC_S += $(ST_CMSIS)/Source/Templates/gcc/startup_stm32l476xx.s
+# IAR
+IAR_SRC_S += $(ST_CMSIS)/Source/Templates/iar/startup_stm32l476xx.s
+IAR_LD_FILE = $(ST_CMSIS)/Source/Templates/iar/linker/stm32l476xx_flash.icf
 
 # For flash-jlink target
 JLINK_DEVICE = stm32l476vg
diff --git a/hw/bsp/stm32l4/boards/stm32l4p5nucleo/board.mk b/hw/bsp/stm32l4/boards/stm32l4p5nucleo/board.mk
index 8252dd838..11edcd9a8 100644
--- a/hw/bsp/stm32l4/boards/stm32l4p5nucleo/board.mk
+++ b/hw/bsp/stm32l4/boards/stm32l4p5nucleo/board.mk
@@ -1,10 +1,13 @@
 CFLAGS += \
   -DSTM32L4P5xx \
 
-# All source paths should be relative to the top level.
-LD_FILE = $(BOARD_PATH)/STM32L4P5ZGTX_FLASH.ld
+# GCC
+GCC_SRC_S += $(ST_CMSIS)/Source/Templates/gcc/startup_stm32l4p5xx.s
+GCC_LD_FILE = $(BOARD_PATH)/STM32L4P5ZGTX_FLASH.ld
 
-SRC_S += $(ST_CMSIS)/Source/Templates/gcc/startup_stm32l4p5xx.s
+# IAR
+IAR_SRC_S += $(ST_CMSIS)/Source/Templates/iar/startup_stm32l4p5xx.s
+IAR_LD_FILE = $(ST_CMSIS)/Source/Templates/iar/linker/stm32l4p5xx_flash.icf
 
 # For flash-jlink target
 JLINK_DEVICE = stm32l4p5zg
diff --git a/hw/bsp/stm32l4/boards/stm32l4r5nucleo/board.mk b/hw/bsp/stm32l4/boards/stm32l4r5nucleo/board.mk
index 3d7fa227b..6dca88a8b 100644
--- a/hw/bsp/stm32l4/boards/stm32l4r5nucleo/board.mk
+++ b/hw/bsp/stm32l4/boards/stm32l4r5nucleo/board.mk
@@ -2,10 +2,13 @@ CFLAGS += \
   -DHSE_VALUE=8000000 \
   -DSTM32L4R5xx \
 
-# All source paths should be relative to the top level.
-LD_FILE = $(BOARD_PATH)/STM32L4RXxI_FLASH.ld
+# GCC
+GCC_SRC_S += $(ST_CMSIS)/Source/Templates/gcc/startup_stm32l4r5xx.s
+GCC_LD_FILE = $(BOARD_PATH)/STM32L4RXxI_FLASH.ld
 
-SRC_S += $(ST_CMSIS)/Source/Templates/gcc/startup_stm32l4r5xx.s
+# IAR
+IAR_SRC_S += $(ST_CMSIS)/Source/Templates/iar/startup_stm32l4r5xx.s
+IAR_LD_FILE = $(ST_CMSIS)/Source/Templates/iar/linker/stm32l4r5xx_flash.icf
 
 # For flash-jlink target
 JLINK_DEVICE = stm32l4r5zi
diff --git a/hw/bsp/stm32l4/family.c b/hw/bsp/stm32l4/family.c
index 0b1443aa0..19b84c086 100644
--- a/hw/bsp/stm32l4/family.c
+++ b/hw/bsp/stm32l4/family.c
@@ -179,7 +179,8 @@ void board_init(void)
 
 void board_led_write(bool state)
 {
-  HAL_GPIO_WritePin(LED_PORT, LED_PIN, state ? LED_STATE_ON : (1-LED_STATE_ON));
+  GPIO_PinState pin_state = (GPIO_PinState) (state ? LED_STATE_ON : (1-LED_STATE_ON));
+  HAL_GPIO_WritePin(LED_PORT, LED_PIN, pin_state);
 }
 
 uint32_t board_button_read(void)
@@ -214,7 +215,7 @@ uint32_t board_millis(void)
 
 void HardFault_Handler (void)
 {
-  asm("bkpt 0x10");
+  __asm("BKPT #0\n");
 }
 
 // Required by __libc_init_array in startup code if we are compiling using
diff --git a/hw/bsp/stm32l4/family.mk b/hw/bsp/stm32l4/family.mk
index 1361e184c..4fab7dc0d 100644
--- a/hw/bsp/stm32l4/family.mk
+++ b/hw/bsp/stm32l4/family.mk
@@ -6,23 +6,36 @@ ST_HAL_DRIVER = hw/mcu/st/stm32$(ST_FAMILY)xx_hal_driver
 
 include $(TOP)/$(BOARD_PATH)/board.mk
 
+# --------------
+# Compiler Flags
+# --------------
 CFLAGS += \
+  -DCFG_TUSB_MCU=OPT_MCU_STM32L4
+
+# GCC Flags
+GCC_CFLAGS += \
   -flto \
   -mthumb \
   -mabi=aapcs \
   -mcpu=cortex-m4 \
   -mfloat-abi=hard \
   -mfpu=fpv4-sp-d16 \
-  -nostdlib -nostartfiles \
-  -DCFG_TUSB_MCU=OPT_MCU_STM32L4
+  -nostdlib -nostartfiles
 
 # suppress warning caused by vendor mcu driver
-CFLAGS += -Wno-error=maybe-uninitialized -Wno-error=cast-align
+GCC_CFLAGS += -Wno-error=maybe-uninitialized -Wno-error=cast-align
+
+# IAR Flags
+IAR_CFLAGS += --cpu cortex-m4 --fpu VFPv4
+IAR_ASFLAGS += --cpu cortex-m4 --fpu VFPv4
+
+# -----------------
+# Sources & Include
+# -----------------
 
-#src/portable/st/synopsys/dcd_synopsys.c
 SRC_C += \
 	src/portable/synopsys/dwc2/dcd_dwc2.c \
-    src/portable/st/stm32_fsdev/dcd_stm32_fsdev.c \
+	src/portable/st/stm32_fsdev/dcd_stm32_fsdev.c \
 	$(ST_CMSIS)/Source/Templates/system_stm32$(ST_FAMILY)xx.c \
 	$(ST_HAL_DRIVER)/Src/stm32$(ST_FAMILY)xx_hal.c \
 	$(ST_HAL_DRIVER)/Src/stm32$(ST_FAMILY)xx_hal_cortex.c \