Raspberry OS Install Tips
Raspberry OS images (formerly “Raspbian”) can be obtained from the Raspberry Pi OS page. These are still 32-bit images, so should run on all models. For the purposes of these hints, the “lite” image is used. Those with a graphical desktop and with additional software should configure in the same way.
In the past one would have had to jump through some hoops to enable SSH and WiFi on first boot. Now, the Raspberry Pi Imager makes this a lot easier, as well as “fixing” puzzling password problems because it came configured for a GB keyboard and you then changed it to your own.
On macOS, you can run it directly from the mounted DMG file, without dragging it to your Applications folder.
Before you write the image, open the hidden advanced-settings screen with cmd+shift+x for macOS or ctrl+shift+x other OSes. You can now preconfigure networking with relative ease.
Make sure you set the WiFi country, or it may not be able to connect.
Enable SSH
Use password authentication
Set password for ‘pi’ user: <enter your new password here>
Configure wifi
SSID: <the name of your access point>
Password: <the password for your access point>
Wifi country <select your country code>
Set locale settings
Time zone: <select yours>
Keyboard layout: <select yours>
Make other changes you might want, then click SAVE
As I don’t use the Raspberry Pi with a graphical desktop, the Lite image is sufficient
Operating System > Raspberry Pi OS (other) > Raspberry Pi OS Lite
As it will be writing to a “raw” device (the microSD), your OS may ask for permissions to write to removable media or similar.
Update OS
Note
See Raspberry Pi 4 and BLE, below, before updating if you have a Pi 4
Do this periodically
pi@raspberrypi:~ $ sudo apt update
pi@raspberrypi:~ $ sudo apt upgrade
pi@raspberrypi:~ $ sudo reboot
Require a Password for sudo
Requiring a password probably makes things a bit more secure.
Confirm if pi (or your user) is in the sudo group first.
pi@raspberrypi:~ $ id
uid=1000(pi) gid=1000(pi) groups=1000(pi),4(adm),20(dialout),24(cdrom),27(sudo),29(audio),44(video),46(plugdev),60(games),100(users),105(input),109(netdev),997(gpio),998(i2c),999(spi)
If not, sudo usermod -a -G sudo pi and recheck.
Confirm that the sudo group is configured for access
with %sudo ALL=(ALL:ALL) ALL
pi@raspberrypi:~ $ sudo fgrep sudo /etc/sudoers
# This file MUST be edited with the 'visudo' command as root.
# Please consider adding local content in /etc/sudoers.d/ instead of
# See the man page for details on how to write a sudoers file.
# Allow members of group sudo to execute any command
%sudo ALL=(ALL:ALL) ALL
# See sudoers(5) for more information on "@include" directives:
@includedir /etc/sudoers.d
Then cross your fingers and comment out the only line in
sudo visudo /etc/sudoers.d/010_pi-nopasswd
# pi ALL=(ALL) NOPASSWD: ALL
Change pi to Something Better
I can make a security argument here for changing the “main” user name, but I’ll admit that convenience for me is a bigger driver. (This is an optional, though recommended step.)
There are four files that map user and group names to numbers and then the name of the “home” directory in one of those. It’s definitely possible to botch this and get locked out. That’s why I do it before there is much time invested. Easier to re-image than to try juggling things.
Warning
This needs to be done in one sudo session, as there are times when
things are inconsistent and you may not be able to authenticate.
pi@raspberrypi:~ $ sudo bash
[sudo] password for pi:
root@raspberrypi:/home/pi# cd /home
root@raspberrypi:/home# ln -s pi jeff
root@raspberrypi:/home# ls -l
total 4
lrwxrwxrwx 1 root root 2 Nov 18 20:51 jeff -> pi
drwxr-xr-x 2 pi pi 4096 Nov 18 21:09 pi
vipw and change pi to jeff (or whatever) in the two places
in the line
pi:x:1000:1000:,,,:/home/pi:/bin/bash
vipw -s and change pi to jeff in the one place in the line
pi:$5$a_bunch_of_apparently_random_characters:18930:0:99999:7:::
vigr and change pi to jeff in lines like
sudo:x:27:pi
pi:x:1000:
(Don’t change spi or gpio or similar)
vigr -s and change pi to jeff similarly
Then complete things by renaming the home directory
root@raspberrypi:/home# rm jeff
root@raspberrypi:/home# mv pi jeff
root@raspberrypi:/home# exit
exit
pi@raspberrypi:~ $ whoami
jeff
pi@raspberrypi:~ $ exit
logout
Next time you log in, log in as your new user name (with the same password)
Add Yourself to bluetooth Group
jeff@pi-walnut:~ $ sudo usermod -a -G bluetooth jeff
That way you can run bluetoothctl without elevated privilege.
Install python3-venv
The Python module to create virtual environments is not installed in the
base image. If $ dpkg --get-selections | fgrep python3 does not list
python3-venv, install it with
sudo apt install python3-venv
There’s no “harm” in installing it if it is already there. apt would mark it
as “manually installed” if it was previously installed as a dependency.
Utilities and Packages I Often Use
sudo apt install git ldnsutils locate sqlite3
ldnsutils provides drill, which I find useful to query DNS
locate is a quick, file-name search across the entire system
that is helpful for “Where are the .service files again?” and the like.
htop is already installed with the Raspberry OS image and is a more
fully featured monitoring tool than top without getting into huge
number of packages that something like glances brings in.
Timekeeping
TL;DR
Unless you’re concerned about tens of milliseconds, skip installing ntp,
stick with the default, but disable dhcpcd from restarting it on every
DHCP renewal.
The default DHCP client, dhcpcd is configured to restart the timekeeping
utility on every lease renewal. Depending on how your router or DHCP server
is set up, this might be every few minutes. This can limit the ability to get
a good estimate of time, as well as causing log spam.
For most people that aren’t moving their computer from network to network
without rebooting it, there is little reason to restart timekeeping with
each DHCP renewal. The “hooks” that do this can be disabled by adding
to the end of /etc/dhcpcd.conf
# Additions start here
nohook hostname ntp-common.conf chrony.conf timesyncd.conf ntp.conf openntpd.conf
The above list comes from examining the hooks in /lib/dhcpcd/dhcpcd-hooks.
Setting of hostname was also disabled, as it is often “permanently” configured
in /etc/hostname and reflected in /etc/hosts.
ntp installs a more sophisticated time-keeping package than the default.
I believe it is more accurate than the default systemd-timesyncd.
systemd-timesyncd apparently has the advantage of persisting
the last-known time to disk and restoring it at boot. This is helpful
for machines that do not have a real-time clock (RTC) that survives
without power, such as on the Raspberry Pi boards. It has a disadvantage
of only using a single time server, without the set of algorithms of NTP
to estimate and stabilize the clock from multiple sources.
The accuracy you get with systemd-timesyncd will depend on which
server gets randomly selected and “Internet weather”.
WiFi Dropouts
My Pi Zero 2 seems to randomly drop off WiFi, even with an ssh session open. There are suggestions that WMM or Fast Roaming are problematic, as well as power control. WMM is primarily related to QoS, but there is a Power Save Certification as well. Reflecting on it, the 3B+ may also have some issues.
Guessing that power control in the Pi is at the core of the problem, especially as it is within a couple meters of the AP and it doesn’t seem to impact other devices on the network
$ iwlist wlan0 power
wlan0 Current mode:on
$ sudo iwconfig wlan0 power off
$ iwlist wlan0 power
wlan0 Current mode:off
seems to have resolved it. One way to make the change permanent is
to create /etc/systemd/system/wlan0_power_mgmt_off.service containing
[Unit]
Description=Disable power-save on wlan0
After=sys-subsystem-net-devices-wlan0.device
[Service]
Type=oneshot
RemainAfterExit=yes
ExecStart=/sbin/iwconfig wlan0 power off
[Install]
WantedBy=sys-subsystem-net-devices-wlan0.device
and enable it with sudo systemctl enable wlan0_power_mgmt_off.service
Unit file after https://raspberrypi.stackexchange.com/questions/96606/make-iw-wlan0-set-power-save-off-permanent
Raspberry Pi 4 and BLE
Important
This applies to the Raspberry Pi 4B only
It appears that the current (January 2022) Raspberry Pi OS updates break the Bluetooth LE functionality on a Raspberry Pi 4B. So far, it has not been seen on a 3B+ or Zero 2, only the 4B. The symptoms are that a device connects, then immediately disconnects. This can be seen using bluetoothctl so is at the OS level, long before bleak or pyDE1 come into play.
Though not confirmed or resolved by the OS maintainers, it seems to be a conflict between the Broadcom WiFi and Bluetooth firmware.
If you have already updated, downgrading the WiFi firmware seems to resolve the issue. Generally available should be the same version presently being used in Debian
sudo apt install firmware-brcm80211=20210315-3
This version can be “held” so that apt upgrade will not automatically
replace it with
sudo apt-mark hold firmware-brcm80211
It is possible that the version presently being installed by the image flasher
is operational as well. Version 1:20210315-3+rpt2 does not appear to be
readily available from the Raspberry Pi repos, but could be held
after installation as indicated above. It has not been investigated if there
are any differences in the +rpt4 version that apply to the specific chips
used for the 4B.