Directly upload the ELF file

Makefile

@@ -1,4 +1,4 @@
-COMPILED:=target/avr-atmega328p/release/blink.elf
+ELF:=target/avr-atmega328p/release/blink.elf
 HEX:=blink.hex
 SERIAL_PORT:=/dev/cu.usbmodem143201
 
@@ -6,26 +6,21 @@ RUSTFLAGS:=-Zverify-llvm-ir
 
 all: ${HEX}
 
-.PHONY: ${COMPILED}
-${COMPILED}:
+.PHONY: ${ELF}
+${ELF}:
 	RUSTFLAGS=${RUSTFLAGS} cargo build -Z build-std=core --target avr-atmega328p.json --release
 
-# Convert binary to an Intel HEX file for upload
-${HEX}: ${COMPILED}
-	avr-objcopy -O ihex -R .eeprom $< $@
-
-# Download the HEX to the board
+# Download the ELF to the board
 .PHONY: program
-program: ${HEX}
-	avrdude -p atmega328p -c arduino -P ${SERIAL_PORT} -U flash:w:$<:i
+program: ${ELF}
+	avrdude -p atmega328p -c arduino -P ${SERIAL_PORT} -D -U flash:w:$<
 
 .PHONY: connect-terminal
 connect-terminal:
 	picocom ${SERIAL_PORT}
 
-
 .PHONY: simulate-avr
-simulate-avr: ${COMPILED}
+simulate-avr: ${ELF}
 	simavr \
 	  -m atmega328p \
 	  -f 16000000 \
@@ -34,5 +29,5 @@ simulate-avr: ${COMPILED}
 	  $<
 
 .PHONY: simulate-gdb
-simulate-gdb: ${COMPILED}
+simulate-gdb: ${ELF}
 	avr-gdb -x simulate.gdbinit -tui $<