For person in China:
download openwrtyun.tar.gz into PC
Then use winscp ( Select SCP protocol) to upload to Yun:
root@Arduino:/mnt/sda1# md5sum openwrtyun.tar.gz
f4351fcf4ebeda3eec702fa98812cf96 openwrtyun.tar.gz
Make sure md5 hash is f4351fcf4ebeda3eec702fa98812cf96