It is recommended to use shell, during upgrade, desktop environment may be restarting and causing screen lock.
To get into shell, after Desktop login menu appear, press Ctrl + Alt + F1. To turn back into Desktop press Ctrl + Alt + F7.Current version
# cat /etc/debian_version
12.11
Edit /etc/apt/source.list
#deb cdrom:[Debian GNU/Linux 12.0.0 _Bookworm_ - Official amd64 NETINST with firmware 20230610-10:21]/ bookworm main non-free-firmware
#main
#deb https://deb.debian.org/debian bookworm main contrib non-free-firmware non-free
deb https://deb.debian.org/debian trixie main contrib non-free-firmware non-free
#mirror auto
#deb http://httpredir.debian.org/debian bookworm main contrib
deb http://httpredir.debian.org/debian trixie main contrib
#security
#deb https://security.debian.org/debian-security bookworm-security main contrib non-free-firmware non-free
deb https://security.debian.org/debian-security trixie-security main contrib non-free-firmware non-free
#update
#deb https://deb.debian.org/debian bookworm-updates main contrib non-free-firmware non-free
deb https://deb.debian.org/debian trixie-updates main contrib non-free-firmware non-free
#backport
#deb http://deb.debian.org/debian bookworm-backports main
deb http://deb.debian.org/debian trixie-backports main
Updating repository
# apt-get update
Hit:1 https://dl.google.com/linux/chrome/deb stable InRelease
Hit:2 https://deb.debian.org/debian trixie InRelease
Hit:3 https://security.debian.org/debian-security trixie-security InRelease
Hit:4 https://deb.debian.org/debian trixie-updates InRelease
Hit:5 http://deb.debian.org/debian trixie-backports InRelease
Hit:6 http://httpredir.debian.org/debian trixie InRelease
Reading package lists... Done
Performing minimal upgrade
# apt upgrade --without-new-pkgs
During minimal upgrade, your system may request you to restart some services, allow it. Take some coffee.....
Restart your Debian. This is optional, just make sure system run proper minimal upgrade.
Performing full upgrade
# apt full-upgrade
Full upgrade may takes sometimes.
Restart your Debian and perform clean up
# apt-get autoclean && apt-get autoremove -y
...
$ cat /etc/debian_version
13.0
$ uname -an
Linux hpkakiang 6.12.38+deb13-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.12.38-1 (2025-07-16) x86_64 GNU/Linux
