Is your system really slow reading the packages list?

A procedure is explained at http://antti-juhani.kaijanaho.fi/newblog/archives/521

I just did this on my NanoPi, so should apply to the NanPI2 as well:
dpkg --clear-avail

(Evidently, dpkg --forget-old-unavail is not required)

Downloaded the dctrl-tools package and ran
sync-available

What a difference!