avr通用bootloder

android bootloder的详细，通过一个月的时间去研究这个bootloder的东西，希望对大家有用，里面只写了大体的框架，其他的就需要大家自己去研究了-the the android bootloder details, through the month' s time to study this bootloder things, we hope to be useful, which is write only the general framework, the othe