diff --git a/nxuart/fw/Makefile b/nxuart/fw/Makefile
index dc153f4..d40c59d 100644
--- a/nxuart/fw/Makefile
+++ b/nxuart/fw/Makefile
@@ -4,6 +4,8 @@ CFLAGS = -g -Wall -Wshadow -Werror \
 NAME=nxuart
 CHIP=atmega48
 
+CLK_MHZ=8
+
 AVR_PREFIX = $(BIN_PATH) avr-
 CC = $(AVR_PREFIX)gcc
 OBJCOPY = $(AVR_PREFIX)objcopy
@@ -23,5 +25,7 @@ upload:	$(NAME).bin
 	scp $(NAME).bin jlime:
 
 prog:
-	ssh jlime avrdude -p atmega48 -c nanonote_$(NAME) \
-	  -e -U flash:w:$(NAME).bin:r
+	ssh jlime avrdude -p atmega48 -c nanonote_$(NAME) -e \
+	  -x clk=$(CLK_MHZ) \
+	  -U flash:w:$(NAME).bin:r \
+	  -U lfuse:w:0x60:m