Setting Up debian-backport Repository On A Raspberry Pi

Sometimes I write these posts because I’ve found something interesting. Sometimes I write them because I’ve done something I want to share. And, sometimes I write them because I don’t want to forget how I did something.

This is the latter.

I was trying to set up the debian-backports repository and after I’d added it to the sources.list file I kept getting this:

GPG error: buster-backports main:The following signatures couldn't be verified because the publickey is not available: NO_PUBKEY

and then a 16-character hex number. To fix it, I did the following:

sudo apt-key adv --recv-keys --keyserver [16-character hex number] [other 16-character hex number (if applicable)]

That seems to have done the trick. Source information from: