diff --git a/Makefile b/Makefile
index 4a78d2c..8508ed1 100644
--- a/Makefile
+++ b/Makefile
@@ -12,7 +12,7 @@ test: test_files
 test_files: $(PROGS) $(C_PROGS)
 
 %.bin: %.s
-	riscv64-unknown-elf-gcc -Wl,-Ttext=0x0 -nostdlib -o $@ $<
+	riscv64-unknown-elf-gcc -march=rv64g -Wl,-Ttext=0x0 -nostdlib -o $@ $<
 	riscv64-unknown-elf-objcopy -O binary $@ $@
 
 %.s: %.c
diff --git a/tests/fib.bin b/tests/fib.bin
index 684f659..681a8c7 100755
Binary files a/tests/fib.bin and b/tests/fib.bin differ