到http://www.busybox.net/downloads/binaries/下载放到sdcard
然后
adb shell
su
mount -o remount,rw -t yaffs2 /dev/block/mtdblock3 /system //保证system可写
这里在android shell 内，sh:cp not found， 解决方法用"cat /mnt/sdcard/busybox > /system/xbin"
于是
cat /mnt/sdcard/busybox > /system/xbin
chmod 755 busybox
busybox ls显示还会乱码，于是
busybox ls --color=never
参考:
http://wangfeng0817.blog.163.com/blog/static/477385032012712777995/
http://www.cnblogs.com/xiaowenji/archive/2011/03/12/1982309.html
http://blog.csdn.net/yxz329130952/article/details/8725050