diff --git a/Makefile b/Makefile
index 96e1ab8a8f..3fdf458da4 100644
--- a/Makefile
+++ b/Makefile
@@ -196,6 +196,9 @@ ifneq ($(CONFIG),)
 TARGET_FLAGS := $(TARGET_FLAGS) -DUSE_CONFIG
 endif
 
+SPEED_OPTIMISED_SRC := ""
+SIZE_OPTIMISED_SRC  := ""
+
 include $(TARGET_PLATFORM_DIR)/mk/$(TARGET_MCU_FAMILY).mk
 
 # openocd specific includes
@@ -464,10 +467,10 @@ $(TARGET_OBJ_DIR)/%.o: %.c
 	$(V1) $(if $(findstring $<,$(NOT_OPTIMISED_SRC)), \
 		$(call compile_file,not optimised,$(CC_NO_OPTIMISATION)) \
 	, \
-		$(if $(findstring $(subst ./src/main/,,$<),$(SPEED_OPTIMISED_SRC)), \
+		$(if $(findstring $(subst ./src/platform/,,$(subst ./src/main/,,$<)),$(SPEED_OPTIMISED_SRC)), \
 			$(call compile_file,speed optimised,$(CC_SPEED_OPTIMISATION)) \
 		, \
-			$(if $(findstring $(subst ./src/main/,,$<),$(SIZE_OPTIMISED_SRC)), \
+			$(if $(findstring $(subst ./src/platform/,,$(subst ./src/main/,,$<)),$(SIZE_OPTIMISED_SRC)), \
 				$(call compile_file,size optimised,$(CC_SIZE_OPTIMISATION)) \
 			, \
 				$(call compile_file,optimised,$(CC_DEFAULT_OPTIMISATION)) \
diff --git a/mk/source.mk b/mk/source.mk
index 9a74d5ca8a..86b9110502 100644
--- a/mk/source.mk
+++ b/mk/source.mk
@@ -82,21 +82,16 @@ COMMON_SRC = \
             cli/cli.c \
             cli/settings.c \
             config/config.c \
-            drivers/adc.c \
             drivers/dshot.c \
             drivers/dshot_dpwm.c \
             drivers/dshot_command.c \
             drivers/buf_writer.c \
             drivers/bus.c \
-            drivers/bus_i2c_config.c \
             drivers/bus_i2c_busdev.c \
             drivers/bus_i2c_utils.c \
             drivers/bus_i2c_soft.c \
             drivers/bus_octospi.c \
             drivers/bus_quadspi.c \
-            drivers/bus_spi.c \
-            drivers/bus_spi_config.c \
-            drivers/bus_spi_pinconfig.c \
             drivers/buttons.c \
             drivers/camera_control.c \
             drivers/display.c \
@@ -111,9 +106,6 @@ COMMON_SRC = \
             drivers/resource.c \
             drivers/serial.c \
             drivers/serial_impl.c \
-            drivers/serial_pinconfig.c \
-            drivers/serial_uart.c \
-            drivers/serial_uart_pinconfig.c \
             drivers/serial_uart_hw.c \
             drivers/sound_beeper.c \
             drivers/stack_check.c \
@@ -236,7 +228,6 @@ COMMON_SRC = \
             drivers/rangefinder/rangefinder_hcsr04.c \
             drivers/rangefinder/rangefinder_lidartf.c \
             drivers/rangefinder/rangefinder_lidarmt.c \
-            drivers/serial_escserial.c \
             drivers/vtx_common.c \
             drivers/vtx_table.c \
             io/dashboard.c \
@@ -405,10 +396,7 @@ ifeq ($(SIMULATOR_BUILD),yes)
 TARGET_FLAGS := -DSIMULATOR_BUILD $(TARGET_FLAGS)
 endif
 
-SPEED_OPTIMISED_SRC := ""
-SIZE_OPTIMISED_SRC  := ""
-
-SPEED_OPTIMISED_SRC := $(SPEED_OPTIMISED_SRC) \
+SPEED_OPTIMISED_SRC += \
             common/encoding.c \
             common/filter.c \
             common/maths.c \
@@ -428,7 +416,6 @@ SPEED_OPTIMISED_SRC := $(SPEED_OPTIMISED_SRC) \
             drivers/accgyro_legacy/accgyro_l3gd20.c \
             drivers/accgyro_legacy/accgyro_lsm303dlhc.c \
             drivers/accgyro_legacy/accgyro_mma845x.c \
-            drivers/adc.c \
             drivers/buf_writer.c \
             drivers/bus.c \
             drivers/bus_quadspi.c \
diff --git a/src/platform/APM32/mk/APM32F4.mk b/src/platform/APM32/mk/APM32F4.mk
index 3f3f02f508..9792482a40 100644
--- a/src/platform/APM32/mk/APM32F4.mk
+++ b/src/platform/APM32/mk/APM32F4.mk
@@ -175,6 +175,15 @@ MCU_COMMON_SRC = \
             adc_apm32f4xx.c \
             dma_apm32f4xx.c \
             serial_uart_apm32f4xx.c \
+            drivers/adc.c \
+            drivers/bus_i2c_config.c \
+            drivers/bus_spi.c \
+            drivers/bus_spi_config.c \
+            drivers/bus_spi_pinconfig.c \
+            drivers/serial_escserial.c \
+            drivers/serial_pinconfig.c \
+            drivers/serial_uart.c \
+            drivers/serial_uart_pinconfig.c \
             system_apm32f4xx.c
 
 VCP_SRC = \
@@ -197,7 +206,7 @@ MSC_SRC = \
             msc/usbd_storage_sdio.c
 
 SPEED_OPTIMISED_SRC += \
-            stm32/system.c
+            common/stm32/system.c
 
 DSP_LIB := $(ROOT)/lib/main/CMSIS/DSP
 DEVICE_FLAGS += -DARM_MATH_MATRIX_CHECK -DARM_MATH_ROUNDING -DUNALIGNED_SUPPORT_DISABLE -DARM_MATH_CM4 -DUSE_FULL_DDL_DRIVER
diff --git a/src/platform/AT32/mk/AT32F4.mk b/src/platform/AT32/mk/AT32F4.mk
index 25d59e9104..89305fe552 100644
--- a/src/platform/AT32/mk/AT32F4.mk
+++ b/src/platform/AT32/mk/AT32F4.mk
@@ -114,12 +114,19 @@ MCU_COMMON_SRC = \
             $(MIDDLEWARES_DIR)/i2c_application_library/i2c_application.c \
             drivers/bus_i2c_timing.c \
             drivers/usb_msc_common.c \
+            drivers/adc.c \
+            drivers/bus_i2c_config.c \
+            drivers/bus_spi.c \
+            drivers/bus_spi_config.c \
+            drivers/bus_spi_pinconfig.c \
+            drivers/serial_escserial.c \
+            drivers/serial_pinconfig.c \
+            drivers/serial_uart.c \
+            drivers/serial_uart_pinconfig.c \
             msc/usbd_storage.c \
             msc/usbd_storage_emfat.c \
             msc/emfat.c \
             msc/emfat_file.c
 
 SPEED_OPTIMISED_SRC += \
-            stm32/system.c
-
-MCU_EXCLUDES =
+            common/stm32/system.c
diff --git a/src/platform/SITL/mk/SITL.mk b/src/platform/SITL/mk/SITL.mk
index d6c92fe215..f9d585d1dd 100644
--- a/src/platform/SITL/mk/SITL.mk
+++ b/src/platform/SITL/mk/SITL.mk
@@ -18,20 +18,6 @@ MCU_FLASH_SIZE  := 2048
 ARM_SDK_PREFIX  =
 
 MCU_EXCLUDES = \
-            drivers/adc.c \
-            drivers/bus_i2c.c \
-            drivers/bus_i2c_config.c \
-            drivers/bus_spi.c \
-            drivers/bus_spi_config.c \
-            drivers/bus_spi_pinconfig.c \
-            drivers/dma.c \
-            drivers/pwm_output.c \
-            drivers/rcc.c \
-            drivers/serial_escserial.c \
-            drivers/serial_pinconfig.c \
-            drivers/serial_uart.c \
-            drivers/serial_uart_init.c \
-            drivers/serial_uart_pinconfig.c \
             drivers/rx/rx_xn297.c \
             drivers/display_ug2864hsweg01.c \
             telemetry/crsf.c \
diff --git a/src/platform/STM32/mk/STM32F4.mk b/src/platform/STM32/mk/STM32F4.mk
index 1e56512e83..ed0274e80a 100644
--- a/src/platform/STM32/mk/STM32F4.mk
+++ b/src/platform/STM32/mk/STM32F4.mk
@@ -202,10 +202,19 @@ MCU_COMMON_SRC = \
             transponder_ir_io_stdperiph.c \
             usbd_msc_desc.c \
             camera_control_stm32.c \
+            drivers/adc.c \
+            drivers/bus_i2c_config.c \
+            drivers/bus_spi.c \
+            drivers/bus_spi_config.c \
+            drivers/bus_spi_pinconfig.c \
+            drivers/serial_escserial.c \
+            drivers/serial_pinconfig.c \
+            drivers/serial_uart.c \
+            drivers/serial_uart_pinconfig.c \
             startup/system_stm32f4xx.c
 
 SPEED_OPTIMISED_SRC += \
-            stm32/system.c
+            common/stm32/system.c
 
 ifeq ($(PERIPH_DRIVER), HAL)
 VCP_SRC = \
diff --git a/src/platform/STM32/mk/STM32F7.mk b/src/platform/STM32/mk/STM32F7.mk
index 942e779a6c..2084b5621a 100644
--- a/src/platform/STM32/mk/STM32F7.mk
+++ b/src/platform/STM32/mk/STM32F7.mk
@@ -171,11 +171,17 @@ MCU_COMMON_SRC = \
             timer_stm32f7xx.c \
             transponder_ir_io_hal.c \
             camera_control_stm32.c \
+            drivers/adc.c \
+            drivers/bus_i2c_config.c \
+            drivers/bus_spi.c \
+            drivers/bus_spi_config.c \
+            drivers/bus_spi_pinconfig.c \
+            drivers/serial_escserial.c \
+            drivers/serial_pinconfig.c \
+            drivers/serial_uart.c \
+            drivers/serial_uart_pinconfig.c \
             startup/system_stm32f7xx.c
 
-MCU_EXCLUDES = \
-            drivers/bus_i2c.c
-
 MSC_SRC = \
             drivers/usb_msc_common.c \
             usb_msc_hal.c \
@@ -187,7 +193,7 @@ MSC_SRC = \
             msc/usbd_storage_sd_spi.c
 
 SPEED_OPTIMISED_SRC += \
-            stm32/system.c
+            common/stm32/system.c
 
 DSP_LIB := $(ROOT)/lib/main/CMSIS/DSP
 DEVICE_FLAGS += -DARM_MATH_MATRIX_CHECK -DARM_MATH_ROUNDING -D__FPU_PRESENT=1 -DUNALIGNED_SUPPORT_DISABLE -DARM_MATH_CM7
diff --git a/src/platform/STM32/mk/STM32G4.mk b/src/platform/STM32/mk/STM32G4.mk
index a5c335ac54..923aca727a 100644
--- a/src/platform/STM32/mk/STM32G4.mk
+++ b/src/platform/STM32/mk/STM32G4.mk
@@ -148,11 +148,17 @@ MCU_COMMON_SRC = \
             timer_stm32g4xx.c \
             transponder_ir_io_hal.c \
             camera_control_stm32.c \
+            drivers/adc.c \
+            drivers/bus_i2c_config.c \
+            drivers/bus_spi.c \
+            drivers/bus_spi_config.c \
+            drivers/bus_spi_pinconfig.c \
+            drivers/serial_escserial.c \
+            drivers/serial_pinconfig.c \
+            drivers/serial_uart.c \
+            drivers/serial_uart_pinconfig.c \
             startup/system_stm32g4xx.c
 
-MCU_EXCLUDES = \
-            drivers/bus_i2c.c
-
 # G4's MSC use the same driver layer file with F7
 MSC_SRC = \
             drivers/usb_msc_common.c \
@@ -165,7 +171,7 @@ MSC_SRC = \
             msc/usbd_storage_sd_spi.c
 
 SPEED_OPTIMISED_SRC += \
-            stm32/system.c
+            common/stm32/system.c
 
 DSP_LIB := $(ROOT)/lib/main/CMSIS/DSP
 DEVICE_FLAGS += -DARM_MATH_MATRIX_CHECK -DARM_MATH_ROUNDING -D__FPU_PRESENT=1 -DUNALIGNED_SUPPORT_DISABLE -DARM_MATH_CM4
diff --git a/src/platform/STM32/mk/STM32H5.mk b/src/platform/STM32/mk/STM32H5.mk
index 7dad4ac4a4..11cdf5d64c 100644
--- a/src/platform/STM32/mk/STM32H5.mk
+++ b/src/platform/STM32/mk/STM32H5.mk
@@ -174,6 +174,15 @@ MCU_COMMON_SRC = \
             transponder_ir_io_hal.c \
             camera_control_stm32.c \
             system_stm32h5xx.c \
+            drivers/adc.c \
+            drivers/bus_i2c_config.c \
+            drivers/bus_spi.c \
+            drivers/bus_spi_config.c \
+            drivers/bus_spi_pinconfig.c \
+            drivers/serial_escserial.c \
+            drivers/serial_pinconfig.c \
+            drivers/serial_uart.c \
+            drivers/serial_uart_pinconfig.c \
             startup/system_stm32h5xx.c
 
 #            memprot_hal.c \
@@ -184,9 +193,6 @@ MCU_COMMON_SRC = \
 #            adc_stm32h5xx.c \
 #            dma_stm32h5xx.c \
 
-MCU_EXCLUDES = \
-            drivers/bus_i2c.c
-
 MSC_SRC =
 #MSC_SRC = \
             usb_msc_hal.c \
@@ -199,7 +205,7 @@ MSC_SRC =
             msc/usbd_storage_sdio.c
 
 SPEED_OPTIMISED_SRC += \
-            stm32/system.c
+            common/stm32/system.c
 
 DSP_LIB := $(ROOT)/lib/main/CMSIS/DSP
 DEVICE_FLAGS += -DARM_MATH_MATRIX_CHECK -DARM_MATH_ROUNDING -DUNALIGNED_SUPPORT_DISABLE -DARM_MATH_CM7
diff --git a/src/platform/STM32/mk/STM32H7.mk b/src/platform/STM32/mk/STM32H7.mk
index 5c62cf43c4..0639cff249 100644
--- a/src/platform/STM32/mk/STM32H7.mk
+++ b/src/platform/STM32/mk/STM32H7.mk
@@ -298,11 +298,17 @@ MCU_COMMON_SRC = \
             timer_stm32h7xx.c \
             transponder_ir_io_hal.c \
             camera_control_stm32.c \
+            drivers/adc.c \
+            drivers/bus_i2c_config.c \
+            drivers/bus_spi.c \
+            drivers/bus_spi_config.c \
+            drivers/bus_spi_pinconfig.c \
+            drivers/serial_escserial.c \
+            drivers/serial_pinconfig.c \
+            drivers/serial_uart.c \
+            drivers/serial_uart_pinconfig.c \
             startup/system_stm32h7xx.c
 
-MCU_EXCLUDES = \
-            drivers/bus_i2c.c
-
 MSC_SRC = \
             usb_msc_hal.c \
             drivers/usb_msc_common.c \
@@ -314,7 +320,7 @@ MSC_SRC = \
             msc/usbd_storage_sdio.c
 
 SPEED_OPTIMISED_SRC += \
-            stm32/system.c
+            common/stm32/system.c
 
 DSP_LIB := $(ROOT)/lib/main/CMSIS/DSP
 DEVICE_FLAGS += -DARM_MATH_MATRIX_CHECK -DARM_MATH_ROUNDING -D__FPU_PRESENT=1 -DUNALIGNED_SUPPORT_DISABLE -DARM_MATH_CM7
diff --git a/src/test/Makefile b/src/test/Makefile
index 7555a7b8e6..dc508f9bbf 100644
--- a/src/test/Makefile
+++ b/src/test/Makefile
@@ -177,8 +177,7 @@ gps_conversion_unittest_SRC := \
 
 io_serial_unittest_SRC := \
 		$(USER_DIR)/io/serial.c \
-		$(USER_DIR)/io/serial_resource.c \
-		$(USER_DIR)/drivers/serial_pinconfig.c
+		$(USER_DIR)/io/serial_resource.c
 
 
 ledstrip_unittest_SRC := \
diff --git a/src/test/unit/io_serial_unittest.cc b/src/test/unit/io_serial_unittest.cc
index b8dd4bc604..4f5a199894 100644
--- a/src/test/unit/io_serial_unittest.cc
+++ b/src/test/unit/io_serial_unittest.cc
@@ -36,6 +36,7 @@ extern "C" {
     void serialInit(bool softserialEnabled, serialPortIdentifier_e serialPortToDisable);
 
     PG_REGISTER(rxConfig_t, rxConfig, PG_RX_CONFIG, 0);
+    PG_REGISTER(serialPinConfig_t, serialPinConfig, PG_SERIAL_PIN_CONFIG, 0);
 }
 
 #include "unittest_macros.h"