Is there any suitable embedded debian/ubuntu apt source server for Chinese users?

I’m a Chinese user, I just know some sources for Chinese desktop debian/ubuntu users. While I can’t access some default sources in the debian/ubuntu of beaglebone black, the speed of others are very slow. Please list some quick sources for Chinese embedded arm users?

ubuntu:

only has one "armhf" repo:

ports.ubuntu.com/ubuntu-ports/

It's based in the 'uk'

debian: has a whole mirror network

Change the default us mirror to cn

ftp.us.debian.org/debian/ -> ftp.cn.debian.org/debian/

Regards,

Thank you!