diff --git a/Marlin/src/HAL/HAL_STM32F1/SoftwareSerial.cpp b/Marlin/src/HAL/HAL_STM32F1/SoftwareSerial.cpp
index 309500d48..99772a03c 100644
--- a/Marlin/src/HAL/HAL_STM32F1/SoftwareSerial.cpp
+++ b/Marlin/src/HAL/HAL_STM32F1/SoftwareSerial.cpp
@@ -16,7 +16,7 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  *
  */
-#ifdef __STM32F1__
+#if defined(__STM32F1__) && !defined(HAVE_SW_SERIAL)
 
 /**
  * Empty class for Software Serial implementation (Custom RX/TX pins)
diff --git a/buildroot/share/PlatformIO/scripts/fysetc_STM32F1.py b/buildroot/share/PlatformIO/scripts/fysetc_STM32F1.py
index 3f45185ac..c34b92145 100644
--- a/buildroot/share/PlatformIO/scripts/fysetc_STM32F1.py
+++ b/buildroot/share/PlatformIO/scripts/fysetc_STM32F1.py
@@ -1,8 +1,7 @@
 from os.path import join
+from os.path import expandvars
 Import("env", "projenv")
 
-platform = env.PioPlatform()
-
 # Relocate firmware from 0x08000000 to 0x08002000
 #env['CPPDEFINES'].remove(("VECT_TAB_ADDR", 134217728))
 #env['CPPDEFINES'].append(("VECT_TAB_ADDR", "0x08010000"))
@@ -10,14 +9,11 @@ platform = env.PioPlatform()
 
 # Custom HEX from ELF
 env.AddPostAction(
-	"$BUILD_DIR/${PROGNAME}.elf",
+	join("$BUILD_DIR","${PROGNAME}.elf"),
 	env.VerboseAction(" ".join([
-				"$OBJCOPY",
-				"-O",
-				"ihex",
-				'"$BUILD_DIR/${PROGNAME}.elf"',
-				'"$BUILD_DIR/${PROGNAME}.hex"'
-			]), "Building $TARGET"))
+		"$OBJCOPY", "-O ihex", "$TARGET", # TARGET=.pio/build/fysetc_STM32F1/firmware.elf
+		"'" + join("$BUILD_DIR","${PROGNAME}.hex") + "'", # Note: $BUILD_DIR is a full path
+	]), "Building $TARGET"))
 
 # please keep $SOURCE variable, it will be replaced with a path to firmware
 
@@ -28,11 +24,15 @@ env.AddPostAction(
 #)
 
 # In-line command with arguments
-env.Replace(
-	UPLOADER=platform.get_package_dir("tool-stm32duino") + '/stm32flash/stm32flash',
-	UPLOADCMD='"${UPLOADER}" -v -i rts,-dtr,dtr,-rts -R -b 115200 -g 0x8000000 -w "${BUILD_DIR}/${PROGNAME}.hex" ${UPLOAD_PORT}'
-)
+UPLOAD_TOOL="stm32flash"
+platform = env.PioPlatform()
+if platform.get_package_dir("tool-stm32duino") != None:
+	UPLOAD_TOOL=expandvars("'" + join(platform.get_package_dir("tool-stm32duino"),"stm32flash","stm32flash") + "'")
 
+env.Replace(
+	UPLOADER=UPLOAD_TOOL,
+	UPLOADCMD=expandvars(UPLOAD_TOOL + " -v -i rts,-dtr,dtr $UPLOAD_PORT -R -w '" + join("$BUILD_DIR","${PROGNAME}.hex") + "'")
+)
 
 # Python callback
 #def on_upload(source, target, env):
diff --git a/platformio.ini b/platformio.ini
index c98b0f4d3..d62388726 100644
--- a/platformio.ini
+++ b/platformio.ini
@@ -280,11 +280,10 @@ monitor_speed = 250000
 platform      = ststm32
 framework     = arduino
 board         = genericSTM32F103RC
-#board_build.core = maple
 extra_scripts = buildroot/share/PlatformIO/scripts/fysetc_STM32F1.py
 build_flags   = !python Marlin/src/HAL/HAL_STM32F1/STM32F1_flag_script.py
   ${common.build_flags} -std=gnu++14
-  -DDEBUG_LEVEL=0
+  -DDEBUG_LEVEL=0 -DHAVE_SW_SERIAL
 build_unflags = -std=gnu++11
 lib_deps      = ${common.lib_deps}
   SoftwareSerialM=https://github.com/FYSETC/SoftwareSerialM/archive/master.zip