We've added some enhancements to our mirror redirect tool the allow you to choose a region.
UPDATE: See Friendlier Documentation Here
The following regions are configured:
NA - North America
EU - Europe
AS - Asia (currently only china)
to use update the url in /etc/apt/sources.list.d/armbian.list from apt.armbian.com to apt.armbian.com/region/REGIONCODE
ex:
# cat /etc/apt/sources.list.d/armbian.list
deb http://apt.armbian.com/region/NA focal main focal-utils focal-desktop
If you'd like to choose a specifc mirror you can query https://apt.armbian.com/mirrors and find a mirror