我想修改Arduino Uno的bootloader（optiboot），以便将上传命令超时从1s增加到8s。所以我需要重新编译bootloaders并上传它。
我能够将弃用的'-mshort-calls'替换为'-mrelax'并且我能够编译它但是它产生了太大的二进制文件：
MBA-Anton:optiboot asmirnov$ make atmega328
../../../../tools/avr/bin/avr-gcc -g -Wall -Os -fno-inline-small-functions -fno-split-wide-types -mrelax -fno-move-loop-invariants -mmcu=atmega328p -DF_CPU=16000000L -mrelax '-DLED_START_FLASHES=3' '-DBAUD_RATE=115200' -c -o optiboot.o optiboot.c
../../../../tools/avr/bin/avr-gcc -g -Wall -Os -fno-inline-small-functions -fno-split-wide-types -mrelax -fno-move-loop-invariants -mmcu=atmega328p -DF_CPU=16000000L -mrelax '-DLED_START_FLASHES=3' '-DBAUD_RATE=115200' -Wl,--section-start=.text=0x7e00 -Wl,--section-start=.version=0x7ffe -Wl,--relax -Wl,--gc-sections -nostartfiles -nostdlib -o optiboot_atmega328.elf optiboot.o
../../../../tools/avr/bin/avr-size optiboot_atmega328.elf
text data bss dec hex filename
530 0 0 530 212 optiboot_atmega328.elf
../../../../tools/avr/bin/avr-objcopy -j .text -j .data -j .version --set-section-flags .version=alloc,load -O ihex optiboot_atmega328.elf optiboot_atmega328.hex
../../../../tools/avr/bin/avr-objdump -h -S optiboot_atmega328.elf > optiboot_atmega328.lst
rm optiboot.o optiboot_atmega328.elf
avr-gcc版本：
MBA-Anton:optiboot asmirnov$ ../../../../tools/avr/bin/avr-gcc --version
avr-gcc (GCC) 4.8.1
Copyright (C) 2013 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
MBA-Anton:optiboot asmirnov$
我用谷歌搜索了更多，我发现same config相当于产生更小的二进制文件，所以出了什么问题呢？