diff --git a/Makefile b/Makefile
index 4b547c4..35fc954 100644
--- a/Makefile
+++ b/Makefile
@@ -16,58 +16,98 @@
 #  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 
 # MMDVM source files
-MMDVM_HS_PATH = .
+MMDVM_HS_PATH := .
+
+
+# Optimization Level
+OPTLVL := s
+
+# Debug Level
+DBGLVL := 0
+
+# C Standard
+CSTD := gnu11
+
+# C++ Standard
+CXXSTD := gnu++14
+
+# sleep delays for multi-stage flashing processes
+STLINK_SLEEP_DELAY := 3
+SERIAL_SLEEP_DELAY := 3
+
 
 # STM32 library paths
-F1_LIB_PATH = ./STM32F10X_Lib
-F4_LIB_PATH = ./STM32F4XX_Lib
-F7_LIB_PATH = ./STM32F7XX_Lib
+F1_LIB_PATH := ./STM32F10X_Lib
+F4_LIB_PATH := ./STM32F4XX_Lib
+F7_LIB_PATH := ./STM32F7XX_Lib
+
 
 # MCU external clock frequency (Hz)
-CLK_PI_F4 = 12000000
-CLK_DEF   = 8000000
+CLK_PI_F4 := 12000000
+CLK_DEF   := 8000000
+
 
 # Directory Structure
-BINDIR    = bin
-OBJDIR_F1 = obj_f1
-OBJDIR_F4 = obj_f4
-OBJDIR_F7 = obj_f7
+BINDIR    := bin
+OBJDIR_F1 := obj_f1
+OBJDIR_F4 := obj_f4
+OBJDIR_F7 := obj_f7
+
 
 # Output files
-BINELF_F1=mmdvm_f1.elf
-BINHEX_F1=mmdvm_f1.hex
-BINBIN_F1=mmdvm_f1.bin
-BINELF_F1BL=mmdvm_f1bl.elf
-BINHEX_F1BL=mmdvm_f1bl.hex
-BINBIN_F1BL=mmdvm_f1bl.bin
-BINELF_F1NOBL=mmdvm_f1nobl.elf
-BINHEX_F1NOBL=mmdvm_f1nobl.hex
-BINBIN_F1NOBL=mmdvm_f1nobl.bin
-BINELF_F4=mmdvm_f4.elf
-BINHEX_F4=mmdvm_f4.hex
-BINBIN_F4=mmdvm_f4.bin
-BINELF_F7=mmdvm_f7.elf
-BINHEX_F7=mmdvm_f7.hex
-BINBIN_F7=mmdvm_f7.bin
+BINELF_F1     = mmdvm_f1.elf
+BINHEX_F1     = mmdvm_f1.hex
+BINBIN_F1     = mmdvm_f1.bin
+
+BINELF_F1BL   = mmdvm_f1bl.elf
+BINHEX_F1BL   = mmdvm_f1bl.hex
+BINBIN_F1BL   = mmdvm_f1bl.bin
+
+BINELF_F1NOBL = mmdvm_f1nobl.elf
+BINHEX_F1NOBL = mmdvm_f1nobl.hex
+BINBIN_F1NOBL = mmdvm_f1nobl.bin
+
+BINELF_F4     = mmdvm_f4.elf
+BINHEX_F4     = mmdvm_f4.hex
+BINBIN_F4     = mmdvm_f4.bin
+
+BINELF_F7     = mmdvm_f7.elf
+BINHEX_F7     = mmdvm_f7.hex
+BINBIN_F7     = mmdvm_f7.bin
+
 
 # Header directories
-INC_F1 = . $(F1_LIB_PATH)/CMSIS/ $(F1_LIB_PATH)/Device/ $(F1_LIB_PATH)/STM32F10x_StdPeriph_Driver/inc/ $(F1_LIB_PATH)/usb/inc/
-INCLUDES_F1 = $(INC_F1:%=-I%)
-INC_F4 = . $(F4_LIB_PATH)/CMSIS/Include/ $(F4_LIB_PATH)/Device/ $(F4_LIB_PATH)/STM32F4xx_StdPeriph_Driver/include/
-INCLUDES_F4 = $(INC_F4:%=-I%)
-INC_F7 = . $(F7_LIB_PATH)/CMSIS/Include/ $(F7_LIB_PATH)/Device/ $(F7_LIB_PATH)/STM32F7xx_StdPeriph_Driver/inc/
-INCLUDES_F7 = $(INC_F7:%=-I%)
+INC_F1      := .
+INC_F1      += $(F1_LIB_PATH)/CMSIS/
+INC_F1      += $(F1_LIB_PATH)/Device/
+INC_F1      += $(F1_LIB_PATH)/STM32F10x_StdPeriph_Driver/inc/
+INC_F1      += $(F1_LIB_PATH)/usb/inc/
+INCLUDES_F1 := $(INC_F1:%=-I%)
+
+INC_F4      := .
+INC_F4      += $(F4_LIB_PATH)/CMSIS/Include/
+INC_F4      += $(F4_LIB_PATH)/Device/
+INC_F4      += $(F4_LIB_PATH)/STM32F4xx_StdPeriph_Driver/include/
+INCLUDES_F4 := $(INC_F4:%=-I%)
+
+INC_F7      := .
+INC_F7      += $(F7_LIB_PATH)/CMSIS/Include/
+INC_F7      += $(F7_LIB_PATH)/Device/
+INC_F7      += $(F7_LIB_PATH)/STM32F7xx_StdPeriph_Driver/inc/
+INCLUDES_F7 := $(INC_F7:%=-I%)
+
 
 # CMSIS libraries
-INCLUDES_LIBS_F1 =
-INCLUDES_LIBS_F4 = $(F4_LIB_PATH)/CMSIS/Lib/GCC/libarm_cortexM4lf_math.a
-INCLUDES_LIBS_F7 = $(F7_LIB_PATH)/CMSIS/Lib/GCC/libarm_cortexM7lfsp_math.a
+INCLUDES_LIBS_F1 :=
+INCLUDES_LIBS_F4 := $(F4_LIB_PATH)/CMSIS/Lib/GCC/libarm_cortexM4lf_math.a
+INCLUDES_LIBS_F7 := $(F7_LIB_PATH)/CMSIS/Lib/GCC/libarm_cortexM7lfsp_math.a
+
 
 # STM32F1 Standard Peripheral Libraries source path
-STD_LIB_F1 = $(F1_LIB_PATH)/STM32F10x_StdPeriph_Driver/src
+STD_LIB_F1 := $(F1_LIB_PATH)/STM32F10x_StdPeriph_Driver/src
 
 # STM32F1 USB support source path
-USB_F1 = $(F1_LIB_PATH)/usb
+USB_F1 := $(F1_LIB_PATH)/usb
 
 # STM32F4 Standard Peripheral Libraries source path
 STD_LIB_F4 = $(F4_LIB_PATH)/STM32F4xx_StdPeriph_Driver/source
@@ -80,53 +120,52 @@ SYS_DIR_F1     = $(F1_LIB_PATH)/Device
 STARTUP_DIR_F1 = $(F1_LIB_PATH)/Device/startup
 
 # STM32F4 system source path
-SYS_DIR_F4=$(F4_LIB_PATH)/Device
-STARTUP_DIR_F4=$(F4_LIB_PATH)/Device/startup
+SYS_DIR_F4     = $(F4_LIB_PATH)/Device
+STARTUP_DIR_F4 = $(F4_LIB_PATH)/Device/startup
 
 # STM32F7 system source path
-SYS_DIR_F7=$(F7_LIB_PATH)/Device
-STARTUP_DIR_F7=$(F7_LIB_PATH)/Device/startup
+SYS_DIR_F7     = $(F7_LIB_PATH)/Device
+STARTUP_DIR_F7 = $(F7_LIB_PATH)/Device/startup
 
 # GNU ARM Embedded Toolchain
 CROSS := arm-none-eabi-
-
-CC   := $(CROSS)gcc
-CXX  := $(CROSS)g++
-LD   := arm-none-eabi-ld
-AR   := arm-none-eabi-ar
-AS   := arm-none-eabi-as
-CP   := arm-none-eabi-objcopy
-OD   := arm-none-eabi-objdump
-NM   := arm-none-eabi-nm
-SIZE := arm-none-eabi-size
-A2L  := arm-none-eabi-addr2line
+CC    := $(CROSS)gcc
+CXX   := $(CROSS)g++
+LD    := $(CROSS)ld
+AR    := $(CROSS)ar
+AS    := $(CROSS)as
+CP    := $(CROSS)objcopy
+OD    := $(CROSS)objdump
+NM    := $(CROSS)nm
+SIZE  := $(CROSS)size
+A2L   := $(CROSS)addr2line
 
 # Configure vars depending on OS
 ifeq ($(OS),Windows_NT)
-	CLEANCMD=del /S *.o *.hex *.bin *.elf
-	MDDIRS=md $@
-	DFU_UTIL=./$(F1_LIB_PATH)/utils/win/dfu-util.exe
-	STM32FLASH=./$(F1_LIB_PATH)/utils/win/stm32flash.exe
+	CLEANCMD   := del /S *.o *.hex *.bin *.elf
+	MDDIRS     := md $@
+	DFU_UTIL   := ./$(F1_LIB_PATH)/utils/win/dfu-util.exe
+	STM32FLASH := ./$(F1_LIB_PATH)/utils/win/stm32flash.exe
 else
-	CLEANCMD=rm -f $(OBJ_F1BL) $(OBJ_F4) $(OBJ_F7) $(BINDIR)/*.hex $(BINDIR)/mmdvm_f1.bin $(BINDIR)/mmdvm_f1bl.bin $(BINDIR)/mmdvm_f1nobl.bin $(BINDIR)/*.elf
-	MDDIRS=mkdir $@
+	CLEANCMD := rm -f $(OBJ_F1) $(OBJ_F1BL) $(OBJ_F4) $(OBJ_F7) $(BINDIR)/*.hex $(BINDIR)/mmdvm_f1.bin $(BINDIR)/mmdvm_f1bl.bin $(BINDIR)/mmdvm_f1nobl.bin $(BINDIR)/*.elf
+	MDDIRS   := mkdir $@
 
 	ifeq ($(shell uname -s),Linux)
-		ST_FLASH_ON_PATH=$(shell which st-flash)
-		ST_FLASH_IS_ON_PATH=$(.SHELLSTATUS)
+		ST_FLASH_ON_PATH    = $(shell which st-flash)
+		ST_FLASH_IS_ON_PATH = $(.SHELLSTATUS)
 		ifeq ($(shell uname -m),x86_64)
-			DFU_RST=./$(F1_LIB_PATH)/utils/linux64/upload-reset
-			DFU_UTIL=./$(F1_LIB_PATH)/utils/linux64/dfu-util
-			DFU_RST=./$(F1_LIB_PATH)/utils/linux64/upload-reset
-			DFU_UTIL=./$(F1_LIB_PATH)/utils/linux64/dfu-util
+			DFU_RST  = ./$(F1_LIB_PATH)/utils/linux64/upload-reset
+			DFU_UTIL = ./$(F1_LIB_PATH)/utils/linux64/dfu-util
+			DFU_RST  = ./$(F1_LIB_PATH)/utils/linux64/upload-reset
+			DFU_UTIL = ./$(F1_LIB_PATH)/utils/linux64/dfu-util
 			ifeq ($(ST_FLASH_IS_ON_PATH),0)
-				ST_FLASH=$(ST_FLASH_ON_PATH)
-				ST_FLASH_OPTS=--flash=128k
+				ST_FLASH = $(ST_FLASH_ON_PATH)
+				ST_FLASH_OPTS = --flash=128k
 			else
-			  ST_FLASH=./$(F1_LIB_PATH)/utils/linux64/st-flash
-				ST_FLASH_OPTS= 
-		  endif
-			STM32FLASH=./$(F1_LIB_PATH)/utils/linux64/stm32flash
+				ST_FLASH = ./$(F1_LIB_PATH)/utils/linux64/st-flash
+				ST_FLASH_OPTS =
+			endif
+			STM32FLASH = ./$(F1_LIB_PATH)/utils/linux64/stm32flash
 		else ifeq ($(shell uname -m),armv7l)
 			DFU_RST=./$(F1_LIB_PATH)/utils/rpi32/upload-reset
 			DFU_UTIL=./$(F1_LIB_PATH)/utils/rpi32/dfu-util
@@ -144,117 +183,133 @@ else
 				ST_FLASH=$(ST_FLASH_ON_PATH)
 				ST_FLASH_OPTS=--flash=128k
 			else
-			  ST_FLASH=./$(F1_LIB_PATH)/utils/linux/st-flash
-				ST_FLASH_OPTS= 
-		  endif
+				ST_FLASH      = ./$(F1_LIB_PATH)/utils/linux/st-flash
+				ST_FLASH_OPTS =
+			endif
 			STM32FLASH=./$(F1_LIB_PATH)/utils/linux/stm32flash
 		endif
 	endif
 
 	ifeq ($(shell uname -s),Darwin)
-		DFU_RST=./$(F1_LIB_PATH)/utils/macosx/upload-reset
-		DFU_UTIL=./$(F1_LIB_PATH)/utils/macosx/dfu-util
-		ST_FLASH=./$(F1_LIB_PATH)/utils/macosx/st-flash
-		STM32FLASH=./$(F1_LIB_PATH)/utils/macosx/stm32flash
+		DFU_RST    = ./$(F1_LIB_PATH)/utils/macosx/upload-reset
+		DFU_UTIL   = ./$(F1_LIB_PATH)/utils/macosx/dfu-util
+		ST_FLASH   = ./$(F1_LIB_PATH)/utils/macosx/st-flash
+		STM32FLASH = ./$(F1_LIB_PATH)/utils/macosx/stm32flash
 	endif
 endif
 
 # Default reference oscillator frequencies
 ifndef $(OSC)
 	ifeq ($(MAKECMDGOALS),pi-f4)
-		OSC=$(CLK_PI_F4)
+		OSC := $(CLK_PI_F4)
 	else
-		OSC=$(CLK_DEF)
+		OSC := $(CLK_DEF)
 	endif
 endif
 
 # Build object lists
-CXXSRC=$(wildcard $(MMDVM_HS_PATH)/*.cpp)
-CSRC_STD_F1=$(wildcard $(STD_LIB_F1)/*.c)
-SYS_F1=$(wildcard $(SYS_DIR_F1)/*.c)
-STARTUP_F1=$(wildcard $(STARTUP_DIR_F1)/*.c)
-CXX_USB_F1=$(wildcard $(USB_F1)/*.cpp)
-C_USB_F1=$(wildcard $(USB_F1)/*.c)
-CSRC_STD_F4=$(wildcard $(STD_LIB_F4)/*.c)
-SYS_F4=$(wildcard $(SYS_DIR_F4)/*.c)
-STARTUP_F4=$(wildcard $(STARTUP_DIR_F4)/*.c)
-CSRC_STD_F7=$(wildcard $(STD_LIB_F7)/*.c)
-SYS_F7=$(wildcard $(SYS_DIR_F7)/*.c)
-STARTUP_F7=$(wildcard $(STARTUP_DIR_F7)/*.c)
-OBJ_F1=$(CXXSRC:$(MMDVM_HS_PATH)/%.cpp=$(OBJDIR_F1)/%.o) $(CSRC_STD_F1:$(STD_LIB_F1)/%.c=$(OBJDIR_F1)/%.o) $(SYS_F1:$(SYS_DIR_F1)/%.c=$(OBJDIR_F1)/%.o) $(STARTUP_F1:$(STARTUP_DIR_F1)/%.c=$(OBJDIR_F1)/%.o) 
-OBJ_F1BL=$(CXXSRC:$(MMDVM_HS_PATH)/%.cpp=$(OBJDIR_F1)/%.o) $(CSRC_STD_F1:$(STD_LIB_F1)/%.c=$(OBJDIR_F1)/%.o) $(SYS_F1:$(SYS_DIR_F1)/%.c=$(OBJDIR_F1)/%.o) $(STARTUP_F1:$(STARTUP_DIR_F1)/%.c=$(OBJDIR_F1)/%.o) $(CXX_USB_F1:$(USB_F1)/%.cpp=$(OBJDIR_F1)/%.o) $(C_USB_F1:$(USB_F1)/%.c=$(OBJDIR_F1)/%.o)
-OBJ_F4=$(CXXSRC:$(MMDVM_HS_PATH)/%.cpp=$(OBJDIR_F4)/%.o) $(CSRC_STD_F4:$(STD_LIB_F4)/%.c=$(OBJDIR_F4)/%.o) $(SYS_F4:$(SYS_DIR_F4)/%.c=$(OBJDIR_F4)/%.o) $(STARTUP_F4:$(STARTUP_DIR_F4)/%.c=$(OBJDIR_F4)/%.o)
-OBJ_F7=$(CXXSRC:$(MMDVM_HS_PATH)/%.cpp=$(OBJDIR_F7)/%.o) $(CSRC_STD_F7:$(STD_LIB_F7)/%.c=$(OBJDIR_F7)/%.o) $(SYS_F7:$(SYS_DIR_F7)/%.c=$(OBJDIR_F7)/%.o) $(STARTUP_F7:$(STARTUP_DIR_F7)/%.c=$(OBJDIR_F7)/%.o)
+CXXSRC      := $(wildcard $(MMDVM_HS_PATH)/*.cpp)
+CSRC_STD_F1 := $(wildcard $(STD_LIB_F1)/*.c)
+SYS_F1      := $(wildcard $(SYS_DIR_F1)/*.c)
+STARTUP_F1  := $(wildcard $(STARTUP_DIR_F1)/*.c)
+CXX_USB_F1  := $(wildcard $(USB_F1)/*.cpp)
+C_USB_F1    := $(wildcard $(USB_F1)/*.c)
+CSRC_STD_F4 := $(wildcard $(STD_LIB_F4)/*.c)
+SYS_F4      := $(wildcard $(SYS_DIR_F4)/*.c)
+STARTUP_F4  := $(wildcard $(STARTUP_DIR_F4)/*.c)
+CSRC_STD_F7 := $(wildcard $(STD_LIB_F7)/*.c)
+SYS_F7      := $(wildcard $(SYS_DIR_F7)/*.c)
+STARTUP_F7  := $(wildcard $(STARTUP_DIR_F7)/*.c)
+
+OBJ_F1   := $(CXXSRC:$(MMDVM_HS_PATH)/%.cpp=$(OBJDIR_F1)/%.o) $(CSRC_STD_F1:$(STD_LIB_F1)/%.c=$(OBJDIR_F1)/%.o) $(SYS_F1:$(SYS_DIR_F1)/%.c=$(OBJDIR_F1)/%.o) $(STARTUP_F1:$(STARTUP_DIR_F1)/%.c=$(OBJDIR_F1)/%.o)
+OBJ_F1BL := $(CXXSRC:$(MMDVM_HS_PATH)/%.cpp=$(OBJDIR_F1)/%.o) $(CSRC_STD_F1:$(STD_LIB_F1)/%.c=$(OBJDIR_F1)/%.o) $(SYS_F1:$(SYS_DIR_F1)/%.c=$(OBJDIR_F1)/%.o) $(STARTUP_F1:$(STARTUP_DIR_F1)/%.c=$(OBJDIR_F1)/%.o) $(CXX_USB_F1:$(USB_F1)/%.cpp=$(OBJDIR_F1)/%.o) $(C_USB_F1:$(USB_F1)/%.c=$(OBJDIR_F1)/%.o)
+OBJ_F4   := $(CXXSRC:$(MMDVM_HS_PATH)/%.cpp=$(OBJDIR_F4)/%.o) $(CSRC_STD_F4:$(STD_LIB_F4)/%.c=$(OBJDIR_F4)/%.o) $(SYS_F4:$(SYS_DIR_F4)/%.c=$(OBJDIR_F4)/%.o) $(STARTUP_F4:$(STARTUP_DIR_F4)/%.c=$(OBJDIR_F4)/%.o)
+OBJ_F7   := $(CXXSRC:$(MMDVM_HS_PATH)/%.cpp=$(OBJDIR_F7)/%.o) $(CSRC_STD_F7:$(STD_LIB_F7)/%.c=$(OBJDIR_F7)/%.o) $(SYS_F7:$(SYS_DIR_F7)/%.c=$(OBJDIR_F7)/%.o) $(STARTUP_F7:$(STARTUP_DIR_F7)/%.c=$(OBJDIR_F7)/%.o)
+
 
 # MCU flags
-MCFLAGS_F1 = -mcpu=cortex-m3 -march=armv7-m -mthumb -Wall -Wextra
-MCFLAGS_F4 = -mcpu=cortex-m4 -mthumb -mlittle-endian -mfpu=fpv4-sp-d16 -mfloat-abi=hard -mthumb-interwork
-MCFLAGS_F7 = -mcpu=cortex-m7 -mthumb -mlittle-endian -mfpu=fpv5-sp-d16 -mfloat-abi=hard -mthumb-interwork
+MCFLAGS_F1 := -mcpu=cortex-m3 -march=armv7-m -mthumb -Wall -Wextra
+MCFLAGS_F4 := -mcpu=cortex-m4 -mthumb -mlittle-endian -mfpu=fpv4-sp-d16 -mfloat-abi=hard -mthumb-interwork
+MCFLAGS_F7 := -mcpu=cortex-m7 -mthumb -mlittle-endian -mfpu=fpv5-sp-d16 -mfloat-abi=hard -mthumb-interwork
+
 
 # Compile flags
-DEFS_F1_HS=-DUSE_STDPERIPH_DRIVER -DSTM32F10X_MD -DHSE_VALUE=$(OSC) -DVECT_TAB_OFFSET=0x0 -DMADEBYMAKEFILE
-DEFS_F1_HS_BL=-DUSE_STDPERIPH_DRIVER -DSTM32F10X_MD -DHSE_VALUE=$(OSC) -DVECT_TAB_OFFSET=0x2000 -DMADEBYMAKEFILE
+DEFS_F1_HS    := -DUSE_STDPERIPH_DRIVER -DSTM32F10X_MD -DHSE_VALUE=$(OSC) -DVECT_TAB_OFFSET=0x0 -DMADEBYMAKEFILE
+DEFS_F1_HS_BL := -DUSE_STDPERIPH_DRIVER -DSTM32F10X_MD -DHSE_VALUE=$(OSC) -DVECT_TAB_OFFSET=0x2000 -DMADEBYMAKEFILE
+
 # STM32F446 Pi-Hat board:
-DEFS_PI_F4=-DUSE_STDPERIPH_DRIVER -DSTM32F4XX -DSTM32F446xx -DSTM32F4_PI -DHSE_VALUE=$(OSC) -DMADEBYMAKEFILE
+DEFS_PI_F4    := -DUSE_STDPERIPH_DRIVER -DSTM32F4XX -DSTM32F446xx -DSTM32F4_PI -DHSE_VALUE=$(OSC) -DMADEBYMAKEFILE
+
 # STM32F4 Nucleo-64 F446RE board:
-DEFS_F446=-DUSE_STDPERIPH_DRIVER -DSTM32F4XX -DSTM32F446xx -DSTM32F4_NUCLEO -DHSE_VALUE=$(OSC) -DMADEBYMAKEFILE
+DEFS_F446     := -DUSE_STDPERIPH_DRIVER -DSTM32F4XX -DSTM32F446xx -DSTM32F4_NUCLEO -DHSE_VALUE=$(OSC) -DMADEBYMAKEFILE
+
 # STM32F7 Nucleo-144 F767ZI board:
-DEFS_F767=-DUSE_HAL_DRIVER -DSTM32F767xx -DSTM32F7XX -DSTM32F7_NUCLEO -DHSE_VALUE=$(OSC) -DMADEBYMAKEFILE
+DEFS_F767     := -DUSE_HAL_DRIVER -DSTM32F767xx -DSTM32F7XX -DSTM32F7_NUCLEO -DHSE_VALUE=$(OSC) -DMADEBYMAKEFILE
+
 
 # Build compiler flags
-CFLAGS_F1   = -c $(MCFLAGS_F1) $(INCLUDES_F1)
-CXXFLAGS_F1 = -c $(MCFLAGS_F1) $(INCLUDES_F1)
-CFLAGS_F4   = -c $(MCFLAGS_F4) $(INCLUDES_F4)
-CXXFLAGS_F4 = -c $(MCFLAGS_F4) $(INCLUDES_F4)
-CFLAGS_F7   = -c $(MCFLAGS_F7) $(INCLUDES_F7)
-CXXFLAGS_F7 = -c $(MCFLAGS_F7) $(INCLUDES_F7)
+CFLAGS_F1   := -c $(MCFLAGS_F1) $(INCLUDES_F1)
+CXXFLAGS_F1 := -c $(MCFLAGS_F1) $(INCLUDES_F1)
+CFLAGS_F4   := -c $(MCFLAGS_F4) $(INCLUDES_F4)
+CXXFLAGS_F4 := -c $(MCFLAGS_F4) $(INCLUDES_F4)
+CFLAGS_F7   := -c $(MCFLAGS_F7) $(INCLUDES_F7)
+CXXFLAGS_F7 := -c $(MCFLAGS_F7) $(INCLUDES_F7)
+
 
 # Linker flags
-LDFLAGS_F1_N  = -T normal.ld $(MCFLAGS_F1) $(INCLUDES_LIBS_F1)
-LDFLAGS_F1_BL = -T bootloader.ld $(MCFLAGS_F1) $(INCLUDES_LIBS_F1)
-LDFLAGS_F4    = -T stm32f4xx_link.ld $(MCFLAGS_F4) $(INCLUDES_LIBS_F4)
-LDFLAGS_F7    = -T stm32f7xx_link.ld $(MCFLAGS_F7) $(INCLUDES_LIBS_F7)
+LDFLAGS_F1_N  := -T normal.ld $(MCFLAGS_F1) $(INCLUDES_LIBS_F1)
+LDFLAGS_F1_BL := -T bootloader.ld $(MCFLAGS_F1) $(INCLUDES_LIBS_F1)
+LDFLAGS_F4    := -T stm32f4xx_link.ld $(MCFLAGS_F4) $(INCLUDES_LIBS_F4)
+LDFLAGS_F7    := -T stm32f7xx_link.ld $(MCFLAGS_F7) $(INCLUDES_LIBS_F7)
+
 
 # Common flags
-CFLAGS   = -Os -ffunction-sections -fdata-sections -nostdlib -DCUSTOM_NEW -DNO_EXCEPTIONS -Wno-unused-parameter -nostdlib
-CXXFLAGS = -Os -fno-exceptions -ffunction-sections -fdata-sections -nostdlib -fno-rtti -DCUSTOM_NEW -DNO_EXCEPTIONS -Wno-unused-parameter
-LDFLAGS  = -Os --specs=nano.specs --specs=nosys.specs
+DEFINES := -DCUSTOM_NEW
+DEFINES += -DNO_EXCEPTIONS
+
+CFLAGS   := -O$(OPTLVL) -ffunction-sections -fdata-sections -nostdlib $(DEFINES) -Wno-unused-parameter -nostdlib
+CXXFLAGS := -O$(OPTLVL) -fno-exceptions -ffunction-sections -fdata-sections -nostdlib -fno-rtti $(DEFINES) -Wno-unused-parameter
+LDFLAGS  := -O$(OPTLVL) --specs=nano.specs --specs=nosys.specs
+
+
 
 # Build Rules
 .PHONY: all release_f1 release_f4 release_f7 hs bl nobl pi-f4 f446 f767 clean
 
 all: hs
 
-pi-f4: CFLAGS+=$(CFLAGS_F4) $(DEFS_PI_F4)
-pi-f4: CXXFLAGS+=$(CXXFLAGS_F4) $(DEFS_PI_F4)
-pi-f4: LDFLAGS+=$(LDFLAGS_F4)
+pi-f4: CFLAGS   += $(CFLAGS_F4) $(DEFS_PI_F4)
+pi-f4: CXXFLAGS += $(CXXFLAGS_F4) $(DEFS_PI_F4)
+pi-f4: LDFLAGS  += $(LDFLAGS_F4)
 pi-f4: release_f4
 
-f446: CFLAGS+=$(CFLAGS_F4) $(DEFS_F446)
-f446: CXXFLAGS+=$(CXXFLAGS_F4) $(DEFS_F446)
-f446: LDFLAGS+=$(LDFLAGS_F4)
+f446: CFLAGS   += $(CFLAGS_F4) $(DEFS_F446)
+f446: CXXFLAGS += $(CXXFLAGS_F4) $(DEFS_F446)
+f446: LDFLAGS  += $(LDFLAGS_F4)
 f446: release_f4
 
-f767: CFLAGS+=$(CFLAGS_F7) $(DEFS_F767)
-f767: CXXFLAGS+=$(CXXFLAGS_F7) $(DEFS_F767)
-f767: LDFLAGS+=$(LDFLAGS_F7)
+f767: CFLAGS   += $(CFLAGS_F7) $(DEFS_F767)
+f767: CXXFLAGS += $(CXXFLAGS_F7) $(DEFS_F767)
+f767: LDFLAGS  += $(LDFLAGS_F7)
 f767: release_f7
 
-hs: CFLAGS+=$(CFLAGS_F1) $(DEFS_F1_HS)
-hs: CXXFLAGS+=$(CXXFLAGS_F1) $(DEFS_F1_HS)
-hs: LDFLAGS+=$(LDFLAGS_F1_N)
+hs: CFLAGS   += $(CFLAGS_F1) $(DEFS_F1_HS)
+hs: CXXFLAGS += $(CXXFLAGS_F1) $(DEFS_F1_HS)
+hs: LDFLAGS  += $(LDFLAGS_F1_N)
 hs: release_f1
 
-bl: CFLAGS+=$(CFLAGS_F1) $(DEFS_F1_HS_BL)
-bl: CXXFLAGS+=$(CXXFLAGS_F1) $(DEFS_F1_HS_BL)
-bl: LDFLAGS+=$(LDFLAGS_F1_BL)
+bl: CFLAGS   += $(CFLAGS_F1) $(DEFS_F1_HS_BL)
+bl: CXXFLAGS += $(CXXFLAGS_F1) $(DEFS_F1_HS_BL)
+bl: LDFLAGS  += $(LDFLAGS_F1_BL)
 bl: release_f1bl
 
-nobl: CFLAGS+=$(CFLAGS_F1) $(DEFS_F1_HS)
-nobl: CXXFLAGS+=$(CXXFLAGS_F1) $(DEFS_F1_HS)
-nobl: LDFLAGS+=$(LDFLAGS_F1_N)
+nobl: CFLAGS   += $(CFLAGS_F1) $(DEFS_F1_HS)
+nobl: CXXFLAGS += $(CXXFLAGS_F1) $(DEFS_F1_HS)
+nobl: LDFLAGS  += $(LDFLAGS_F1_N)
 nobl: release_f1nobl
 
+
+
 release_f1: GitVersion.h
 release_f1: $(BINDIR)
 release_f1: $(OBJDIR_F1)
@@ -285,6 +340,8 @@ release_f7: $(OBJDIR_F7)
 release_f7: $(BINDIR)/$(BINHEX_F7)
 release_f7: $(BINDIR)/$(BINBIN_F7)
 
+
+
 $(BINDIR):
 	$(MDDIRS)
 
@@ -418,42 +475,53 @@ $(OBJDIR_F1)/%.o: $(USB_F1)/%.c
 	$(CC) $(CFLAGS) $< -o $@
 	@echo "Compiled "$<"!\n"
 
+
 clean:
+	@echo "Cleaning project...\n"
 	$(CLEANCMD)
 	$(RM) GitVersion.h
 
+
 stlink:
 	$(ST_FLASH) $(ST_FLASH_OPTS) write bin/$(BINBIN_F1) 0x8000000
 
+
 stlink-nobl:
 	$(ST_FLASH) $(ST_FLASH_OPTS) write bin/$(BINBIN_F1NOBL) 0x8000000
 
+
 stlink-bl:
 	$(ST_FLASH) $(ST_FLASH_OPTS) write $(F1_LIB_PATH)/utils/bootloader/generic_boot20_pc13_long_rst.bin 0x8000000
-	sleep 3
+	sleep $(STLINK_SLEEP_DELAY)
 	$(ST_FLASH) $(ST_FLASH_OPTS) write bin/$(BINBIN_F1BL) 0x8002000
 
+
 stlink-bl-old:
 	$(ST_FLASH) $(ST_FLASH_OPTS) write $(F1_LIB_PATH)/utils/bootloader/generic_boot20_pc13.bin 0x8000000
-	sleep 3
+	sleep $(STLINK_SLEEP_DELAY)
 	$(ST_FLASH) $(ST_FLASH_OPTS) write bin/$(BINBIN_F1BL) 0x8002000
 
+
 serial:
 	$(STM32FLASH) -v -w bin/$(BINBIN_F1) -g 0x0 $(devser)
 
+
 serial-nobl:
 	$(STM32FLASH) -v -w bin/$(BINBIN_F1NOBL) -g 0x0 $(devser)
 
+
 serial-bl:
 	$(STM32FLASH) -v -w $(F1_LIB_PATH)/utils/bootloader/generic_boot20_pc13_long_rst.bin -g 0x0 $(devser)
-	sleep 3
+	sleep $(SERIAL_SLEEP_DELAY)
 	$(STM32FLASH) -v -w bin/$(BINBIN_F1BL) -g 0x0 -S 0x08002000 $(devser)
 
+
 serial-bl-old:
 	$(STM32FLASH) -v -w $(F1_LIB_PATH)/utils/bootloader/generic_boot20_pc13.bin -g 0x0 $(devser)
-	sleep 3
+	sleep $(SERIAL_SLEEP_DELAY)
 	$(STM32FLASH) -v -w bin/$(BINBIN_F1BL) -g 0x0 -S 0x08002000 $(devser)
 
+
 nano-hotspot:
 ifneq ($(wildcard /usr/local/bin/stm32flash),)
 	/usr/local/bin/stm32flash -v -w bin/$(BINBIN_F1) -g 0x0 -R -i 200,-3,3:-200,3 /dev/ttyAMA0
@@ -463,6 +531,7 @@ ifneq ($(wildcard /usr/bin/stm32flash),)
 	/usr/bin/stm32flash -v -w bin/$(BINBIN_F1) -g 0x0 -R -i 200,-3,3:-200,3 /dev/ttyAMA0
 endif
 
+
 nano-dv:
 ifneq ($(wildcard /usr/local/bin/stm32flash),)
 	/usr/local/bin/stm32flash -v -w bin/$(BINBIN_F1) -g 0x0 -R -i 66,-67,67:-66,67 /dev/ttyAMA0
@@ -472,6 +541,7 @@ ifneq ($(wildcard /usr/bin/stm32flash),)
 	/usr/bin/stm32flash -v -w bin/$(BINBIN_F1) -g 0x0 -R -i 66,-67,67:-66,67 /dev/ttyAMA0
 endif
 
+
 d2rg_mmdvm_hs:
 ifneq ($(wildcard /usr/local/bin/stm32flash),)
 	/usr/local/bin/stm32flash -v -w bin/$(BINBIN_F1) -g 0x0 -R -i 23,-22,22:-23,22 /dev/ttySC0
@@ -481,6 +551,7 @@ ifneq ($(wildcard /usr/bin/stm32flash),)
 	/usr/bin/stm32flash -v -w bin/$(BINBIN_F1) -g 0x0 -R -i 23,-22,22:-23,22 /dev/ttySC0
 endif
 
+
 zumspot-pi:
 ifneq ($(wildcard /usr/local/bin/stm32flash),)
 	/usr/local/bin/stm32flash -v -w bin/$(BINBIN_F1) -g 0x0 -R -i 20,-21,21:-20,21 /dev/ttyAMA0
@@ -490,12 +561,16 @@ ifneq ($(wildcard /usr/bin/stm32flash),)
 	/usr/bin/stm32flash -v -w bin/$(BINBIN_F1) -g 0x0 -R -i 20,-21,21:-20,21 /dev/ttyAMA0
 endif
 
+
 mmdvm_hs_hat: zumspot-pi
 
+
 mmdvm_hs_dual_hat: zumspot-pi
 
+
 skybridge: zumspot-pi
 
+
 hotpot-opipc_opipcplus:
 ifneq ($(wildcard /usr/local/bin/stm32flash),)
 	/usr/local/bin/stm32flash -v -w bin/$(BINBIN_F1) -g 0x0 -R -i 198,-199,199:-198,199 /dev/ttyS3
@@ -505,16 +580,20 @@ ifneq ($(wildcard /usr/bin/stm32flash),)
 	/usr/bin/stm32flash -v -w bin/$(BINBIN_F1) -g 0x0 -R -i 198,-199,199:-198,199 /dev/ttyS3
 endif
 
+
 mmdvm_hs_hat_opi: hotpot-opipc_opipcplus
 
+
 mmdvm_hs_dual_hat_opi: hotpot-opipc_opipcplus
 
+
 dfu:
 ifdef devser
 	$(DFU_RST) $(devser) 750
 endif
 	$(DFU_UTIL) -D bin/$(BINBIN_F1BL) -d 1eaf:0003 -a 2 -R -R
 
+
 ocd:
 ifneq ($(wildcard /usr/bin/openocd),)
 	/usr/bin/openocd -f /usr/share/openocd/scripts/interface/stlink-v2-1.cfg -f /usr/share/openocd/scripts/target/stm32f1x.cfg -c "program bin/$(BINELF_F1) verify reset exit"
@@ -528,6 +607,7 @@ ifneq ($(wildcard /opt/openocd/bin/openocd),)
 	/opt/openocd/bin/openocd -f /opt/openocd/scripts/interface/stlink-v2-1.cfg -f /opt/openocd/share/openocd/scripts/target/stm32f1x.cfg -c "program bin/$(BINELF_F1) verify reset exit"
 endif
 
+
 ocd-nobl:
 ifneq ($(wildcard /usr/bin/openocd),)
 	/usr/bin/openocd -f /usr/share/openocd/scripts/interface/stlink-v2-1.cfg -f /usr/share/openocd/scripts/target/stm32f1x.cfg -c "program bin/$(BINELF_F1NOBL) verify reset exit"
@@ -541,6 +621,7 @@ ifneq ($(wildcard /opt/openocd/bin/openocd),)
 	/opt/openocd/bin/openocd -f /opt/openocd/scripts/interface/stlink-v2-1.cfg -f /opt/openocd/share/openocd/scripts/target/stm32f1x.cfg -c "program bin/$(BINELF_F1NOBL) verify reset exit"
 endif
 
+
 ocd-bl:
 ifneq ($(wildcard /usr/bin/openocd),)
 	/usr/bin/openocd -f /usr/share/openocd/scripts/interface/stlink-v2-1.cfg -f /usr/share/openocd/scripts/target/stm32f1x.cfg -c "program $(F1_LIB_PATH)/utils/bootloader/generic_boot20_pc13_long_rst.bin verify reset exit 0x08000000"
@@ -557,6 +638,7 @@ ifneq ($(wildcard /opt/openocd/bin/openocd),)
 	/opt/openocd/bin/openocd -f /opt/openocd/scripts/interface/stlink-v2-1.cfg -f /opt/openocd/share/openocd/scripts/target/stm32f1x.cfg -c "program bin/$(BINBIN_F1BL) verify reset exit 0x08002000"
 endif
 
+
 ocd-bl-old:
 ifneq ($(wildcard /usr/bin/openocd),)
 	/usr/bin/openocd -f /usr/share/openocd/scripts/interface/stlink-v2-1.cfg -f /usr/share/openocd/scripts/target/stm32f1x.cfg -c "program $(F1_LIB_PATH)/utils/bootloader/generic_boot20_pc13.bin verify reset exit 0x08000000"
@@ -573,6 +655,7 @@ ifneq ($(wildcard /opt/openocd/bin/openocd),)
 	/opt/openocd/bin/openocd -f /opt/openocd/scripts/interface/stlink-v2-1.cfg -f /opt/openocd/share/openocd/scripts/target/stm32f1x.cfg -c "program bin/$(BINBIN_F1BL) verify reset exit 0x08002000"
 endif
 
+
 # Export the current git version if the index file exists, else 000...
 GitVersion.h: .FORCE
 ifdef SYSTEMROOT