Is there an alternate repository to the debian-mirror.sakura.ne.jp used in /etc/apt/sources.list? The aforementioned address is down.
Thanks!
LasVegas
you can choose one or more from this mirror list
https://www.debian.org/mirror/list
One of the first things I do is of course [Update] in the GameShell [Settings] menu.
After that I fully upgrade the system using my own country’s repository:
# Make a backup of the Japanese repository
sudo cp /etc/apt/sources.list /etc/apt/sources.list.jp
# Replace with your repository with [cc] being your country code (de, fr, ru)!
sudo sed -i -- 's/debian-mirror.sakura.ne.jp/ftp.[cc].debian.org/' /etc/apt/sources.list
# Update repository and upgrade system
sudo apt update
sudo apt -y full-upgrade
It works over here, but break at your own risk. 
Hence, the backup! 
Thanks!