1 files changed, 1 insertions, 1 deletions

diff --git a/tmk_core/rules.mk b/tmk_core/rules.mk
index fc2dc68be..597f7aa82 100644
--- a/tmk_core/rules.mk
+++ b/tmk_core/rules.mk
@@ -458,7 +458,7 @@ ifeq ($(findstring avr-gcc,$(CC)),avr-gcc)
 SIZE_MARGIN = 1024
 
 check-size:
-        $(eval MAX_SIZE=$(shell n=`$(CC) -E -mmcu=$(MCU) $(CFLAGS) $(OPT_DEFS) tmk_core/common/avr/bootloader_size.c 2> /dev/null | sed -ne 's/\r//;/^#/n;/^AVR_SIZE:/,$${s/^AVR_SIZE: //;p;}'` && echo $$(($$n)) || echo 0))
+        $(eval MAX_SIZE=$(shell n=`$(CC) -E -mmcu=$(MCU) -D__ASSEMBLER__ $(CFLAGS) $(OPT_DEFS) tmk_core/common/avr/bootloader_size.c 2> /dev/null | sed -ne 's/\r//;/^#/n;/^AVR_SIZE:/,$${s/^AVR_SIZE: //;p;}'` && echo $$(($$n)) || echo 0))
         $(eval CURRENT_SIZE=$(shell if [ -f $(BUILD_DIR)/$(TARGET).hex ]; then $(SIZE) --target=$(FORMAT) $(BUILD_DIR)/$(TARGET).hex | $(AWK) 'NR==2 {print $$4}'; else printf 0; fi))
         $(eval FREE_SIZE=$(shell expr $(MAX_SIZE) - $(CURRENT_SIZE)))
         $(eval OVER_SIZE=$(shell expr $(CURRENT_SIZE) - $(MAX_SIZE)))