刷个recovery，老是报错：
sudo fastboot flash recovery Downloads/recovery.img
(bootloader) Variable not supported!
target reported max download size of 31457280 bytes
sending ‘recovery‘ (6954 KB)...
FAILED (data transfer failure (Value too large for defined data type))
finished. total time: 0.028s
找了半天资料，最后测试得出原因，因为用了个1转4usb转接器影响的，直接用线接电脑usb口就传输正常了。
原文：http://wangyanwen.blog.51cto.com/1207461/1681968