diff --git a/Makefile b/Makefile
index 50fecf3..fa4c1f0 100644
--- a/Makefile
+++ b/Makefile
@@ -91,10 +91,10 @@ clean:
 	rm -rf *.o *.elf *.lst *.map *.sym *.lss *.eep *.srec *.bin *.hex *.al *.i *.s *~
 
 size: $(PROGRAM).elf
-	@echo "  SIZE                   Atmega168        Atmega328p"
-	@$(OBJDUMP) -h $^ | perl -ne '/.(text)\s+([0-9a-f]+)/ && do { $$a += eval "0x$$2" }; END { printf "    FLASH : %5d bytes  (%2d%% of %2dkb)    (%2d%% of %2dkb)\n", $$a, $$a * 100 / (14 * 1024), 14, $$a * 100 / (30 * 1024), 30 }'
-	@$(OBJDUMP) -h $^ | perl -ne '/.(data|bss)\s+([0-9a-f]+)/ && do { $$a += eval "0x$$2" }; END { printf "    RAM   : %5d bytes  (%2d%% of %2dkb)    (%2d%% of %2dkb)\n", $$a, $$a * 100 / (1 * 1024), 1, $$a * 100 / (2 * 1024), 2 }'
-	@$(OBJDUMP) -h $^ | perl -ne '/.(eeprom)\s+([0-9a-f]+)/ && do { $$a += eval "0x$$2" }; END { printf "    EEPROM: %5d bytes  (%2d%% of %2dkb)    (%2d%% of %2dkb)\n", $$a, $$a * 100 / (1 * 1024), 1, $$a * 100 / (2 * 1024), 2 }'
+	@echo "  SIZE                   Atmega168        Atmega328p       Atmega644"
+	@$(OBJDUMP) -h $^ | perl -ne '/.(text)\s+([0-9a-f]+)/ && do { $$a += eval "0x$$2" }; END { printf "    FLASH : %5d bytes  (%2d%% of %2dkb)    (%2d%% of %2dkb)    (%2d%% of %2dkb)\n", $$a, $$a * 100 / (14 * 1024), 14, $$a * 100 / (30 * 1024), 30, $$a * 100 / (63 * 1024), 63 }'
+	@$(OBJDUMP) -h $^ | perl -ne '/.(data|bss)\s+([0-9a-f]+)/ && do { $$a += eval "0x$$2" }; END { printf "    RAM   : %5d bytes  (%2d%% of %2dkb)    (%2d%% of %2dkb)    (%2d%% of %2dkb)\n", $$a, $$a * 100 / (1 * 1024), 1, $$a * 100 / (2 * 1024), 2, $$a * 100 / (4 * 1024), 4 }'
+	@$(OBJDUMP) -h $^ | perl -ne '/.(eeprom)\s+([0-9a-f]+)/ && do { $$a += eval "0x$$2" }; END { printf "    EEPROM: %5d bytes  (%2d%% of %2dkb)    (%2d%% of %2dkb)    (%2d%% of %2dkb)\n", $$a, $$a * 100 / (1 * 1024), 1, $$a * 100 / (2 * 1024), 2, $$a * 100 / (2 * 1024), 2 }'
 
 config.h: config.h.dist
 	@echo "Please review config.h, as config.h.dist is more recent."
diff --git a/arduino.h b/arduino.h
index 29fb9eb..25425e6 100644
--- a/arduino.h
+++ b/arduino.h
@@ -19,10 +19,10 @@
 
 #define		_READ(IO)					(IO ## _RPORT & MASK(IO ## _PIN))
 #define		_WRITE(IO, v)			do { if (v) { IO ## _WPORT |= MASK(IO ## _PIN); } else { IO ## _WPORT &= ~MASK(IO ## _PIN); }; } while (0)
-#define		_TOGGLE(IO)				(IO ## _RPORT = MASK(IO ## _PIN))
+#define		_TOGGLE(IO)				do { IO ## _RPORT = MASK(IO ## _PIN) } while (0)
 
-#define		_SET_INPUT(IO)		(IO ## _DDR &= ~MASK(IO ## _PIN))
-#define		_SET_OUTPUT(IO)		(IO ## _DDR |=  MASK(IO ## _PIN))
+#define		_SET_INPUT(IO)		do { IO ## _DDR &= ~MASK(IO ## _PIN) } while (0)
+#define		_SET_OUTPUT(IO)		do { IO ## _DDR |=  MASK(IO ## _PIN) } while (0)
 
 #define		_GET_INPUT(IO)		((IO ## _DDR & MASK(IO ## _PIN)) == 0)
 #define		_GET_OUTPUT(IO)		((IO ## _DDR & MASK(IO ## _PIN)) != 0)
@@ -394,15 +394,15 @@
 	#define AIO5_WPORT	PORTA
 	#define AIO5_DDR		DDRA
 
-	#define AIO6_PIN		PINA5
-	#define AIO5_RPORT	PINA
-	#define AIO5_WPORT	PORTA
-	#define AIO5_DDR		DDRA
+	#define AIO6_PIN		PINA6
+	#define AIO6_RPORT	PINA
+	#define AIO6_WPORT	PORTA
+	#define AIO6_DDR		DDRA
 
-	#define AIO7_PIN		PINA5
-	#define AIO5_RPORT	PINA
-	#define AIO5_WPORT	PORTA
-	#define AIO5_DDR		DDRA
+	#define AIO7_PIN		PINA7
+	#define AIO7_RPORT	PINA
+	#define AIO7_WPORT	PORTA
+	#define AIO7_DDR		DDRA
 #endif
 
 #if defined (__AVR_ATmega1280__)
diff --git a/serial.c b/serial.c
index f592973..7f20197 100644
--- a/serial.c
+++ b/serial.c
@@ -48,6 +48,7 @@ volatile uint8_t txbuf[BUFSIZE];
 */
 
 #ifdef	XONXOFF
+#define		FLOWFLAG_STATE_XOFF	0
 #define		FLOWFLAG_SEND_XON		1
 #define		FLOWFLAG_SEND_XOFF	2
 #define		FLOWFLAG_STATE_XON	4
@@ -91,7 +92,7 @@ ISR(USART0_RX_vect)
 	}
 
 	#ifdef	XONXOFF
-	if (flowflags & FLOWFLAG_STATE_XON && buf_canread(rx) >= BUFSIZE - 16) {
+	if (flowflags & FLOWFLAG_STATE_XON && buf_canwrite(rx) <= 16) {
 		// the buffer has only 16 free characters left, so send an XOFF
 		// more characters might come in until the XOFF takes effect
 		flowflags = FLOWFLAG_SEND_XOFF | FLOWFLAG_STATE_XON;
@@ -114,7 +115,7 @@ ISR(USART0_UDRE_vect)
 	}
 	else if (flowflags & FLOWFLAG_SEND_XOFF) {
 		UDR0 = ASCII_XOFF;
-		flowflags = 0;
+		flowflags = FLOWFLAG_STATE_XOFF;
 	}
 	else
 	#endif
diff --git a/temp.c b/temp.c
index 517e6d1..7e818c7 100644
--- a/temp.c
+++ b/temp.c
@@ -191,7 +191,7 @@ void temp_print() {
 		c = (current_temp & 3) * 25;
 		t = (target_temp & 3) * 25;
 		#ifdef REPRAP_HOST_COMPATIBILITY
-		sersendf_P(PSTR("T: %u.%u\n"), current_temp >> 2, c);
+		sersendf_P(PSTR(" T: %u.%u\n"), current_temp >> 2, c);
 		#else
 		sersendf_P(PSTR("T: %u.%u/%u.%u :%u\n"), current_temp >> 2, c, target_temp >> 2, t, temp_residency);
 		#endif