How to Upgrade Debian 9 and Fix Common GNOME3 & Network‑Manager Issues

Preparation before upgrading

Back up the following files and directories before starting the upgrade:

/usr/share/gnome-shell/theme/gnome-shell.css

(needed for GNOME 3 optimizations after the upgrade)

/etc/apt

(easier to restore software source settings later)

/etc

(configuration files for services such as dnsmasq, tftp, apache, vsftpd, etc.)

New Network‑Manager issues and solutions

2.1 Network‑Manager device‑management

Debian 9 ships Network‑Manager version

1.6.2-3

. The old method of marking devices as unmanaged no longer works. Use the following command to set a device to unmanaged mode:

<code>nmcli device set {interface_name} managed no</code>

For example:

<code>nmcli device set eth0 managed no</code>

To revert to managed mode, replace

no

with

yes

. Check the current status with:

<code>nmcli device status</code>

2.2 Wi‑Fi MAC‑address randomization

Since Network‑Manager 1.4.0, MAC randomization is enabled by default, causing the MAC address of a USB Wi‑Fi adapter to change on each plug‑in. To disable this feature, edit

/etc/NetworkManager/NetworkManager.conf

and add a

[device]

section with the appropriate parameters, then restart the service:

<code>systemctl restart NetworkManager.service</code>

2.3 Touch‑pad tap disabled

After the upgrade, tap‑to‑click may stop working. Verify the current settings:

<code>synclient | grep TapButton</code>

If the values are

0

, edit

/usr/share/X11/xorg.conf.d/70-synaptics.conf

and add the necessary parameters after the existing

no

section (see the screenshot). Save the file and restart the GNOME 3 desktop; tap and two‑finger tap should be restored.

GNOME 3 issues and solutions

3.1 Adjusting the window title bar

Older Debian versions allowed modifying the title bar height via a

sed

command on

/usr/share/themes/Adwaita/metacity-1/metacity-theme-3.xml

. In Debian 9 this file no longer exists. Instead, create or edit

~/.config/gtk-3.0/gtk.css

and add the required CSS (see screenshot). Press

ALT+F2

, type

r

, and restart the desktop to see the reduced title bar height.

3.2 Top‑bar (task bar) optimization

In Debian 8 you could edit

/usr/share/gnome-shell/theme/gnome-shell.css

to change the height and background color of the top bar. In Debian 9 the file is missing. Create the directory

/usr/share/themes/Adwaita/gnome-shell

, place a copy of the old

gnome-shell.css

there, and then select the Adwaita theme. Restart the desktop service to apply the changes.

Useful GNOME 3 extensions and tools

The following extensions improve the GNOME 3 experience. Installation methods are shown in the accompanying screenshots.

NetSpeed – displays real‑time network traffic on the top bar.

dash‑to‑dock – enhances the dock with transparency, auto‑hide, and other features.

workspaces‑to‑dock – provides mouse‑triggered workspace switching.

CoverflowAltTab – adds a 3‑D visual switcher for open windows.

Pomodoro – integrates a customizable Pomodoro timer.

Docky – adds a dock at the bottom of the screen for easy application management.

Guake – a drop‑down terminal invoked with

F12

(or a custom shortcut).

screen – a terminal multiplexer supporting split screens.

These extensions can be downloaded from the GNOME extensions website or its GitHub mirrors.