diff --git a/src/platforms/f4discovery/Makefile.inc b/src/platforms/f4discovery/Makefile.inc
index 5470d656..ed4bde72 100644
--- a/src/platforms/f4discovery/Makefile.inc
+++ b/src/platforms/f4discovery/Makefile.inc
@@ -7,7 +7,7 @@ CFLAGS += -Istm32/include -mcpu=cortex-m4 -mthumb \
 	-DSTM32F4 -DF4DISCOVERY -I../libopencm3/include \
 	-Iplatforms/stm32
 
-LDFLAGS_BOOT = -lopencm3_stm32f4 -Wl,--defsym,_stack=0x20020000 \
+LDFLAGS_BOOT := $(LDFLAGS) -lopencm3_stm32f4 -Wl,--defsym,_stack=0x20020000 \
 	-Wl,-T,platforms/stm32/f4discovery.ld -nostartfiles -lc -lnosys \
 	-Wl,-Map=mapfile -mthumb -mcpu=cortex-m4 -Wl,-gc-sections \
 	-mfloat-abi=hard -mfpu=fpv4-sp-d16 \
diff --git a/src/platforms/native/Makefile.inc b/src/platforms/native/Makefile.inc
index 77c07e91..cc4da0bb 100644
--- a/src/platforms/native/Makefile.inc
+++ b/src/platforms/native/Makefile.inc
@@ -6,7 +6,7 @@ CFLAGS += -Istm32/include -mcpu=cortex-m3 -mthumb \
 	-DSTM32F1 -DBLACKMAGIC -I../libopencm3/include \
 	-Iplatforms/stm32
 
-LDFLAGS_BOOT = -lopencm3_stm32f1 -Wl,--defsym,_stack=0x20005000 \
+LDFLAGS_BOOT := $(LDFLAGS) -lopencm3_stm32f1 -Wl,--defsym,_stack=0x20005000 \
 	-Wl,-T,platforms/stm32/blackmagic.ld -nostartfiles -lc -lnosys \
 	-Wl,-Map=mapfile -mthumb -mcpu=cortex-m3 -Wl,-gc-sections \
 	-L../libopencm3/lib
diff --git a/src/platforms/stlink/Makefile.inc b/src/platforms/stlink/Makefile.inc
index 62760d55..1f465880 100644
--- a/src/platforms/stlink/Makefile.inc
+++ b/src/platforms/stlink/Makefile.inc
@@ -5,7 +5,8 @@ OBJCOPY = $(CROSS_COMPILE)objcopy
 CFLAGS += -mcpu=cortex-m3 -mthumb \
 	-DSTM32F1 -DDISCOVERY_STLINK -I../libopencm3/include \
 	-I platforms/stm32
-LDFLAGS_BOOT = --specs=nano.specs -lopencm3_stm32f1 -Wl,--defsym,_stack=0x20005000 \
+LDFLAGS_BOOT := $(LDFLAGS) --specs=nano.specs \
+	-lopencm3_stm32f1 -Wl,--defsym,_stack=0x20005000 \
 	-Wl,-T,platforms/stm32/stlink.ld -nostartfiles -lc -lnosys \
 	-Wl,-Map=mapfile -mthumb -mcpu=cortex-m3 -Wl,-gc-sections \
 	-L../libopencm3/lib
diff --git a/src/platforms/swlink/Makefile.inc b/src/platforms/swlink/Makefile.inc
index df0b648b..ff349db3 100644
--- a/src/platforms/swlink/Makefile.inc
+++ b/src/platforms/swlink/Makefile.inc
@@ -5,7 +5,8 @@ OBJCOPY = $(CROSS_COMPILE)objcopy
 CFLAGS += -mcpu=cortex-m3 -mthumb \
 	-DSTM32F1 -DDISCOVERY_SWLINK -I../libopencm3/include \
 	-I platforms/stm32
-LDFLAGS_BOOT = -lopencm3_stm32f1 -Wl,--defsym,_stack=0x20005000 \
+LDFLAGS_BOOT := $(LDFLAGS) --specs=nano.specs \
+	-lopencm3_stm32f1 -Wl,--defsym,_stack=0x20005000 \
 	-Wl,-T,platforms/stm32/stlink.ld -nostartfiles -lc -lnosys \
 	-Wl,-Map=mapfile -mthumb -mcpu=cortex-m3 -Wl,-gc-sections \
 	-L../libopencm3/lib