diff --git a/Makefile b/Makefile
index 8ffd81b..ff7ae92 100755
--- a/Makefile
+++ b/Makefile
@@ -1,5 +1,9 @@
 TARGET = firmware
 
+ENABLE_AIRCOPY := 1
+ENABLE_OVERLAY := 1
+ENABLE_UART := 1
+
 BSP_DEFINITIONS := $(wildcard hardware/*/*.def)
 BSP_HEADERS := $(patsubst hardware/%,bsp/%,$(BSP_DEFINITIONS))
 BSP_HEADERS := $(patsubst %.def,%.h,$(BSP_HEADERS))
@@ -8,18 +12,26 @@ OBJS =
 # Startup files
 OBJS += start.o
 OBJS += init.o
+ifeq ($(ENABLE_OVERLAY),1)
 OBJS += sram-overlay.o
+endif
 OBJS += external/printf/printf.o
 
 # Drivers
 OBJS += driver/adc.o
+ifeq ($(ENABLE_UART),1)
 OBJS += driver/aes.o
+endif
 OBJS += driver/backlight.o
 OBJS += driver/bk1080.o
 OBJS += driver/bk4819.o
+ifeq ($(filter $(ENABLE_AIRCOPY) $(ENABLE_UART),1),1)
 OBJS += driver/crc.o
+endif
 OBJS += driver/eeprom.o
+ifeq ($(ENABLE_OVERLAY),1)
 OBJS += driver/flash.o
+endif
 OBJS += driver/gpio.o
 OBJS += driver/i2c.o
 OBJS += driver/keyboard.o
@@ -27,11 +39,15 @@ OBJS += driver/spi.o
 OBJS += driver/st7565.o
 OBJS += driver/system.o
 OBJS += driver/systick.o
+ifeq ($(ENABLE_UART),1)
 OBJS += driver/uart.o
+endif
 
 # Main
 OBJS += app/action.o
+ifeq ($(ENABLE_AIRCOPY),1)
 OBJS += app/aircopy.o
+endif
 OBJS += app/app.o
 OBJS += app/dtmf.o
 OBJS += app/fm.o
@@ -39,7 +55,9 @@ OBJS += app/generic.o
 OBJS += app/main.o
 OBJS += app/menu.o
 OBJS += app/scanner.o
+ifeq ($(ENABLE_UART),1)
 OBJS += app/uart.o
+endif
 OBJS += audio.o
 OBJS += bitmaps.o
 OBJS += board.o
@@ -53,7 +71,9 @@ OBJS += misc.o
 OBJS += radio.o
 OBJS += scheduler.o
 OBJS += settings.o
+ifeq ($(ENABLE_AIRCOPY),1)
 OBJS += ui/aircopy.o
+endif
 OBJS += ui/battery.o
 OBJS += ui/fmradio.o
 OBJS += ui/helper.o
@@ -76,7 +96,7 @@ else
 TOP := $(shell pwd)
 endif
 
-AS = arm-none-eabi-as
+AS = arm-none-eabi-gcc
 CC = arm-none-eabi-gcc
 LD = arm-none-eabi-gcc
 OBJCOPY = arm-none-eabi-objcopy
@@ -84,10 +104,22 @@ SIZE = arm-none-eabi-size
 
 GIT_HASH := $(shell git rev-parse --short HEAD)
 
-ASFLAGS = -mcpu=cortex-m0
+ASFLAGS = -c -mcpu=cortex-m0
+ifeq ($(ENABLE_OVERLAY),1)
+ASFLAGS += -DENABLE_OVERLAY
+endif
 CFLAGS = -Os -Wall -Werror -mcpu=cortex-m0 -fno-builtin -fshort-enums -fno-delete-null-pointer-checks -std=c11 -MMD
 CFLAGS += -DPRINTF_INCLUDE_CONFIG_H
 CFLAGS += -DGIT_HASH=\"$(GIT_HASH)\"
+ifeq ($(ENABLE_AIRCOPY),1)
+CFLAGS += -DENABLE_AIRCOPY
+endif
+ifeq ($(ENABLE_OVERLAY),1)
+CFLAGS += -DENABLE_OVERLAY
+endif
+ifeq ($(ENABLE_UART),1)
+CFLAGS += -DENABLE_UART
+endif
 LDFLAGS = -mcpu=cortex-m0 -nostartfiles -Wl,-T,firmware.ld
 
 ifeq ($(DEBUG),1)
diff --git a/app/app.c b/app/app.c
index addb695..1bb2b51 100644
--- a/app/app.c
+++ b/app/app.c
@@ -16,7 +16,9 @@
 
 #include <string.h>
 #include "app/action.h"
+#if defined(ENABLE_AIRCOPY)
 #include "app/aircopy.h"
+#endif
 #include "app/app.h"
 #include "app/dtmf.h"
 #include "app/fm.h"
@@ -24,7 +26,9 @@
 #include "app/main.h"
 #include "app/menu.h"
 #include "app/scanner.h"
+#if defined(ENABLE_UART)
 #include "app/uart.h"
+#endif
 #include "ARMCM0.h"
 #include "audio.h"
 #include "board.h"
@@ -44,7 +48,9 @@
 #include "misc.h"
 #include "radio.h"
 #include "settings.h"
+#if defined(ENABLE_OVERLAY)
 #include "sram-overlay.h"
+#endif
 #include "ui/battery.h"
 #include "ui/inputbox.h"
 #include "ui/menu.h"
@@ -535,6 +541,7 @@ void APP_CheckRadioInterrupts(void)
 			g_SquelchLost = false;
 			BK4819_ToggleGpioOut(BK4819_GPIO0_PIN28_GREEN, false);
 		}
+#if defined(ENABLE_AIRCOPY)
 		if (Mask & BK4819_REG_02_FSK_FIFO_ALMOST_FULL && gScreenToDisplay == DISPLAY_AIRCOPY && gAircopyState == AIRCOPY_TRANSFER && gAirCopyIsSendMode == 0) {
 			uint8_t i;
 
@@ -543,6 +550,7 @@ void APP_CheckRadioInterrupts(void)
 			}
 			AIRCOPY_StorePacket();
 		}
+#endif
 	}
 }
 
@@ -732,7 +740,11 @@ void APP_CheckKeys(void)
 {
 	KEY_Code_t Key;
 
-	if (gSetting_KILLED || (gScreenToDisplay == DISPLAY_AIRCOPY && gAircopyState != AIRCOPY_READY)) {
+	if (gSetting_KILLED
+#if defined(ENABLE_AIRCOPY)
+		|| (gScreenToDisplay == DISPLAY_AIRCOPY && gAircopyState != AIRCOPY_READY)
+#endif
+		) {
 		return;
 	}
 
@@ -802,11 +814,13 @@ void APP_TimeSlice10ms(void)
 {
 	gFlashLightBlinkCounter++;
 
+#if defined(ENABLE_UART)
 	if (UART_IsCommandAvailable()) {
 		__disable_irq();
 		UART_HandleCommand();
 		__enable_irq();
 	}
+#endif
 
 	if (gReducedService) {
 		return;
@@ -987,6 +1001,7 @@ void APP_TimeSlice10ms(void)
 		}
 	}
 
+#if defined(ENABLE_AIRCOPY)
 	if (gScreenToDisplay == DISPLAY_AIRCOPY && gAircopyState == AIRCOPY_TRANSFER && gAirCopyIsSendMode == 1) {
 		if (gAircopySendCountdown) {
 			gAircopySendCountdown--;
@@ -996,6 +1011,7 @@ void APP_TimeSlice10ms(void)
 			}
 		}
 	}
+#endif
 
 	APP_CheckKeys();
 }
@@ -1020,7 +1036,11 @@ void APP_TimeSlice500ms(void)
 	if (gReducedService) {
 		BOARD_ADC_GetBatteryInfo(&gBatteryCurrentVoltage, &gBatteryCurrent);
 		if (gBatteryCurrent > 500 || gBatteryCalibration[3] < gBatteryCurrentVoltage) {
+#if defined(ENABLE_OVERLAY)
 			overlay_FLASH_RebootToBootloader();
+#else
+			NVIC_SystemReset();
+#endif
 		}
 		return;
 	}
@@ -1048,7 +1068,11 @@ void APP_TimeSlice500ms(void)
 					GPIO_ClearBit(&GPIOB->DATA, GPIOB_PIN_BACKLIGHT);
 				}
 			}
-			if (gScreenToDisplay != DISPLAY_AIRCOPY && (gScreenToDisplay != DISPLAY_SCANNER || (gScanCssState >= SCAN_CSS_STATE_FOUND))) {
+			if (
+#if defined(ENABLE_AIRCOPY)
+				gScreenToDisplay != DISPLAY_AIRCOPY &&
+#endif
+				(gScreenToDisplay != DISPLAY_SCANNER || (gScanCssState >= SCAN_CSS_STATE_FOUND))) {
 				if (gEeprom.AUTO_KEYPAD_LOCK && gKeyLockCountdown && !gDTMF_InputMode) {
 					gKeyLockCountdown--;
 					if (gKeyLockCountdown == 0) {
@@ -1406,13 +1430,19 @@ static void APP_ProcessKey(KEY_Code_t Key, bool bKeyPressed, bool bKeyHeld)
 			case DISPLAY_SCANNER:
 				SCANNER_ProcessKeys(Key, bKeyPressed, bKeyHeld);
 				break;
+#if defined(ENABLE_AIRCOPY)
 			case DISPLAY_AIRCOPY:
 				AIRCOPY_ProcessKeys(Key, bKeyPressed, bKeyHeld);
 				break;
+#endif
 			default:
 				break;
 			}
-		} else if (gScreenToDisplay != DISPLAY_SCANNER && gScreenToDisplay != DISPLAY_AIRCOPY) {
+		} else if (gScreenToDisplay != DISPLAY_SCANNER
+#if defined(ENABLE_AIRCOPY)
+				&& gScreenToDisplay != DISPLAY_AIRCOPY
+#endif
+			) {
 			ACTION_Handle(Key, bKeyPressed, bKeyHeld);
 		} else if (!bKeyHeld && bKeyPressed) {
 			gBeepToPlay = BEEP_500HZ_60MS_DOUBLE_BEEP_OPTIONAL;
diff --git a/app/menu.c b/app/menu.c
index 20a4bd8..b092fdb 100644
--- a/app/menu.c
+++ b/app/menu.c
@@ -15,6 +15,9 @@
  */
 
 #include <string.h>
+#if !defined(ENABLE_OVERLAY)
+#include "ARMCM0.h"
+#endif
 #include "app/dtmf.h"
 #include "app/generic.h"
 #include "app/menu.h"
@@ -28,7 +31,9 @@
 #include "frequencies.h"
 #include "misc.h"
 #include "settings.h"
+#if defined(ENABLE_OVERLAY)
 #include "sram-overlay.h"
+#endif
 #include "ui/inputbox.h"
 #include "ui/menu.h"
 #include "ui/ui.h"
@@ -980,7 +985,11 @@ static void MENU_Key_MENU(bool bKeyPressed, bool bKeyHeld)
 						AUDIO_SetVoiceID(0, VOICE_ID_CONFIRM);
 						AUDIO_PlaySingleVoice(true);
 						MENU_AcceptSetting();
+#if defined(ENABLE_OVERLAY)
 						overlay_FLASH_RebootToBootloader();
+#else
+						NVIC_SystemReset();
+#endif
 					}
 					gFlagAcceptSetting = true;
 					gIsInSubMenu = false;
diff --git a/app/uart.c b/app/uart.c
index 4af7319..c2d68b4 100644
--- a/app/uart.c
+++ b/app/uart.c
@@ -15,6 +15,9 @@
  */
 
 #include <string.h>
+#if !defined(ENABLE_OVERLAY)
+#include "ARMCM0.h"
+#endif
 #include "app/fm.h"
 #include "app/uart.h"
 #include "board.h"
@@ -29,7 +32,9 @@
 #include "functions.h"
 #include "misc.h"
 #include "settings.h"
+#if defined(ENABLE_OVERLAY)
 #include "sram-overlay.h"
+#endif
 #include "version.h"
 
 #define DMA_INDEX(x, y) (((x) + (y)) % sizeof(UART_DMA_Buffer))
@@ -510,7 +515,11 @@ void UART_HandleCommand(void)
 		break;
 
 	case 0x05DD:
+#if defined(ENABLE_OVERLAY)
 		overlay_FLASH_RebootToBootloader();
+#else
+		NVIC_SystemReset();
+#endif
 		break;
 	}
 }
diff --git a/audio.c b/audio.c
index 347717a..8d5a300 100644
--- a/audio.c
+++ b/audio.c
@@ -69,9 +69,11 @@ void AUDIO_PlayBeep(BEEP_Type_t Beep)
 		return;
 	}
 
+#if defined(ENABLE_AIRCOPY)
 	if (gScreenToDisplay == DISPLAY_AIRCOPY) {
 		return;
 	}
+#endif
 	if (gCurrentFunction == FUNCTION_RECEIVE) {
 		return;
 	}
diff --git a/board.c b/board.c
index 3a9ef2c..78c955f 100644
--- a/board.c
+++ b/board.c
@@ -36,8 +36,11 @@
 #include "helper/battery.h"
 #include "misc.h"
 #include "settings.h"
+#if defined(ENABLE_OVERLAY)
 #include "sram-overlay.h"
+#endif
 
+#if defined(ENABLE_OVERLAY)
 void BOARD_FLASH_Init(void)
 {
 	FLASH_Init(FLASH_READ_MODE_1_CYCLE);
@@ -47,6 +50,7 @@ void BOARD_FLASH_Init(void)
 	overlay_FLASH_ClockMultiplier = 48;
 	FLASH_Init(FLASH_READ_MODE_2_CYCLE);
 }
+#endif
 
 void BOARD_GPIO_Init(void)
 {
@@ -336,7 +340,9 @@ void BOARD_Init(void)
 	BOARD_ADC_Init();
 	ST7565_Init();
 	BK1080_Init(0, false);
+#if defined(ENABLE_AIRCOPY) || defined(ENABLE_UART)
 	CRC_Init();
+#endif
 }
 
 void BOARD_EEPROM_Init(void)
diff --git a/driver/bk4819.c b/driver/bk4819.c
index 438c1e9..70f8a9b 100644
--- a/driver/bk4819.c
+++ b/driver/bk4819.c
@@ -491,6 +491,7 @@ void BK4819_TurnsOffTones_TurnsOnRX(void)
 			);
 }
 
+#if defined(ENABLE_AIRCOPY)
 void BK4819_SetupAircopy(void)
 {
 	BK4819_WriteRegister(BK4819_REG_70, 0x00E0); // Enable Tone2, tuning gain 48
@@ -508,6 +509,7 @@ void BK4819_ResetFSK(void)
 	SYSTEM_DelayMs(30);
 	BK4819_Idle();
 }
+#endif
 
 void BK4819_Idle(void)
 {
@@ -828,6 +830,7 @@ uint8_t BK4819_GetCTCType(void)
 	return (BK4819_ReadRegister(BK4819_REG_0C) >> 10) & 3;
 }
 
+#if defined(ENABLE_AIRCOPY)
 void BK4819_SendFSKData(uint16_t *pData)
 {
 	uint8_t i;
@@ -882,6 +885,7 @@ void BK4819_PrepareFSKReceive(void)
 	// FSK SyncLength Selection
 	BK4819_WriteRegister(BK4819_REG_59, 0x3068);
 }
+#endif
 
 void BK4819_PlayRoger(void)
 {
diff --git a/helper/boot.c b/helper/boot.c
index a4c5548..d6c6ccd 100644
--- a/helper/boot.c
+++ b/helper/boot.c
@@ -46,9 +46,11 @@ BOOT_Mode_t BOOT_GetMode(void)
 		if (Keys[0] == KEY_SIDE1) {
 			return BOOT_MODE_F_LOCK;
 		}
+#if defined(ENABLE_AIRCOPY)
 		if (Keys[0] == KEY_SIDE2) {
 			return BOOT_MODE_AIRCOPY;
 		}
+#endif
 	}
 
 	return BOOT_MODE_NORMAL;
@@ -62,6 +64,7 @@ void BOOT_ProcessMode(BOOT_Mode_t Mode)
 		GUI_SelectNextDisplay(DISPLAY_MENU);
 		gMenuListCount = 57;
 		gF_LOCK = true;
+#if defined(ENABLE_AIRCOPY)
 	} else if (Mode == BOOT_MODE_AIRCOPY) {
 		gEeprom.DUAL_WATCH = DUAL_WATCH_OFF;
 		gEeprom.BATTERY_SAVE = 0;
@@ -83,6 +86,7 @@ void BOOT_ProcessMode(BOOT_Mode_t Mode)
 		BK4819_ResetFSK();
 		gAircopyState = AIRCOPY_READY;
 		GUI_SelectNextDisplay(DISPLAY_AIRCOPY);
+#endif
 	} else {
 		GUI_SelectNextDisplay(DISPLAY_MAIN);
 	}
diff --git a/main.c b/main.c
index f509419..16386a7 100644
--- a/main.c
+++ b/main.c
@@ -26,7 +26,9 @@
 #include "driver/gpio.h"
 #include "driver/system.h"
 #include "driver/systick.h"
+#if defined(ENABLE_UART)
 #include "driver/uart.h"
+#endif
 #include "helper/battery.h"
 #include "helper/boot.h"
 #include "misc.h"
@@ -35,11 +37,15 @@
 #include "ui/lock.h"
 #include "ui/welcome.h"
 
+#if defined(ENABLE_UART)
 static const char Version[] = "UV-K5 Firmware, Open Edition, OEFW-"GIT_HASH"\r\n";
+#endif
 
 void _putchar(char c)
 {
+#if defined(ENABLE_UART)
 	UART_Send((uint8_t *)&c, 1);
+#endif
 }
 
 void Main(void)
@@ -61,8 +67,10 @@ void Main(void)
 	SYSTICK_Init();
 	BOARD_Init();
 
+#if defined(ENABLE_UART)
 	UART_Init();
 	UART_Send(Version, sizeof(Version));
+#endif
 
 	// Not implementing authentic device checks
 
diff --git a/misc.c b/misc.c
index cdf9424..1058ebd 100644
--- a/misc.c
+++ b/misc.c
@@ -119,7 +119,9 @@ uint8_t gPttDebounceCounter;
 uint8_t gMenuListCount;
 uint8_t gBackupCROSS_BAND_RX_TX;
 uint8_t gScanDelay;
+#if defined(ENABLE_AIRCOPY)
 uint8_t gAircopySendCountdown;
+#endif
 uint8_t gFSKWriteIndex;
 uint8_t gNeverUsed;
 
diff --git a/misc.h b/misc.h
index fb20117..b6e0ffd 100644
--- a/misc.h
+++ b/misc.h
@@ -170,7 +170,9 @@ extern uint8_t gPttDebounceCounter;
 extern uint8_t gMenuListCount;
 extern uint8_t gBackupCROSS_BAND_RX_TX;
 extern uint8_t gScanDelay;
+#if defined(ENABLE_AIRCOPY)
 extern uint8_t gAircopySendCountdown;
+#endif
 extern uint8_t gFSKWriteIndex;
 extern uint8_t gNeverUsed;
 
diff --git a/settings.c b/settings.c
index af67444..8cf0525 100644
--- a/settings.c
+++ b/settings.c
@@ -17,7 +17,9 @@
 #include <string.h>
 #include "app/fm.h"
 #include "driver/eeprom.h"
+#if defined(ENABLE_UART)
 #include "driver/uart.h"
+#endif
 #include "misc.h"
 #include "settings.h"
 
@@ -33,7 +35,9 @@ void SETTINGS_SaveFM(void)
 		uint8_t Padding[4];
 	} State;
 
+#if defined(ENABLE_UART)
 	UART_LogSend("sFm\r\n", 5);
+#endif
 
 	memset(&State, 0xFF, sizeof(State));
 	State.Channel = gEeprom.FM_SelectedChannel;
@@ -50,7 +54,9 @@ void SETTINGS_SaveVfoIndices(void)
 {
 	uint8_t State[8];
 
+#if defined(ENABLE_UART)
 	UART_LogSend("sidx\r\n", 6);
+#endif
 
 	State[0] = gEeprom.ScreenChannel[0];
 	State[1] = gEeprom.MrChannel[0];
@@ -69,7 +75,9 @@ void SETTINGS_SaveSettings(void)
 	uint8_t State[8];
 	uint32_t Password[2];
 
+#if defined(ENABLE_UART)
 	UART_LogSend("spub\r\n", 6);
+#endif
 
 	State[0] = gEeprom.CHAN_1_CALL;
 	State[1] = gEeprom.SQUELCH_LEVEL;
@@ -168,7 +176,9 @@ void SETTINGS_SaveSettings(void)
 
 void SETTINGS_SaveChannel(uint8_t Channel, uint8_t VFO, const VFO_Info_t *pVFO, uint8_t Mode)
 {
+#if defined(ENABLE_UART)
 	UART_LogSend("schn\r\n", 6);
+#endif
 
 	if (IS_NOT_NOAA_CHANNEL(Channel)) {
 		uint16_t OffsetMR;
@@ -222,7 +232,9 @@ void SETTINGS_SaveChannel(uint8_t Channel, uint8_t VFO, const VFO_Info_t *pVFO,
 
 void SETTINGS_UpdateChannel(uint8_t Channel, const VFO_Info_t *pVFO, bool bUpdate)
 {
+#if defined(ENABLE_UART)
 	UART_LogSend("svalid\r\n", 8);
+#endif
 
 	if (IS_NOT_NOAA_CHANNEL(Channel)) {
 		uint8_t State[8];
diff --git a/start.S b/start.S
index 7399bb9..eb29dd7 100644
--- a/start.S
+++ b/start.S
@@ -245,7 +245,9 @@ HandlerReset:
 	mov	sp, r0
 	bl	DATA_Init
 	bl	BSS_Init
+#if defined(ENABLE_OVERLAY)
 	bl	BOARD_FLASH_Init
+#endif
 	bl	Main
 	b 	.
 
diff --git a/ui/lock.c b/ui/lock.c
index 3fb2d5f..1b67910 100644
--- a/ui/lock.c
+++ b/ui/lock.c
@@ -16,7 +16,9 @@
 
 #include <string.h>
 #include "ARMCM0.h"
+#if defined(ENABLE_UART)
 #include "app/uart.h"
+#endif
 #include "audio.h"
 #include "driver/keyboard.h"
 #include "driver/st7565.h"
@@ -109,11 +111,13 @@ void UI_DisplayLock(void)
 			gKeyReading0 = Key;
 		}
 
+#if defined(ENABLE_UART)
 		if (UART_IsCommandAvailable()) {
 			__disable_irq();
 			UART_HandleCommand();
 			__enable_irq();
 		}
+#endif
 
 		if (gUpdateDisplay) {
 			Render();
diff --git a/ui/ui.c b/ui/ui.c
index a174826..b8ca84b 100644
--- a/ui/ui.c
+++ b/ui/ui.c
@@ -20,7 +20,9 @@
 #include "app/scanner.h"
 #include "driver/keyboard.h"
 #include "misc.h"
+#if defined(ENABLE_AIRCOPY)
 #include "ui/aircopy.h"
+#endif
 #include "ui/fmradio.h"
 #include "ui/inputbox.h"
 #include "ui/main.h"
@@ -50,9 +52,11 @@ void GUI_DisplayScreen(void)
 	case DISPLAY_SCANNER:
 		UI_DisplayScanner();
 		break;
+#if defined(ENABLE_AIRCOPY)
 	case DISPLAY_AIRCOPY:
 		UI_DisplayAircopy();
 		break;
+#endif
 	default:
 		break;
 	}
diff --git a/ui/ui.h b/ui/ui.h
index f2809a1..d8a0b61 100644
--- a/ui/ui.h
+++ b/ui/ui.h
@@ -25,7 +25,9 @@ enum GUI_DisplayType_t {
 	DISPLAY_FM	= 0x01U,
 	DISPLAY_MENU	= 0x02U,
 	DISPLAY_SCANNER	= 0x03U,
+#if defined(ENABLE_AIRCOPY)
 	DISPLAY_AIRCOPY	= 0x04U,
+#endif
 	DISPLAY_INVALID	= 0xFFU,
 };