Common information about the Raspberry Pi, my projects based on that computer, and other useful stuff around the “Pi”. Refer also to the page with the Linux Stuff for information related to the Linux operating system in general.
The official documentation for Raspberry Pi computers and microcontrollers. The Raspi Imager can be found here.
Information on how to install the Raspberry Camera, and how to use it.
Information on how to use a Raspberry Pi as a USB device (like a keyboard or a harddrive) for another computer. Mainly Raspberry Pi Zero models are used for this purpose, but also Pi 4 and Pi 5 can be used this way.
The Compute Modules are an alternative to a ‘real’ Raspberry Pi for the use in embedded systems. They lack the connectors of the Raspberry Pi, these needs to be provided by the host board. But they come with built-in eMMC memory (if not the lite version), so there is no need for an external MicroSD card for the operating system.
How to install the operating system on a CM5 is described here.
Unsorted notes about various features of the Raspberry Pi and components to use with it.
/dev/zram0The Raspberry Pi 5 is quite particular about power supplies. Many “powerful” mobile phone chargers deliver 25W or more, but often at higher voltages (9V, 12V) and not at the 5V/5A required by the Raspi, while weaker power supplies really do not provide sufficient power.
The message “This power supply is not capable to deliver 5A …” (or a small yellow lightning bolt icon in the upper right corner of the screen) appears on the Raspberry Pi 5 because it communicates with the power supply via the “USB-C Power Delivery (PD)” protocol. If the power supply doesn’t signal that it can deliver 5A at 5V, the Raspi reduces the current to the USB ports (from 1.6A to 600mA) as a safety precaution to prevent system crashes.
The command vcgencmd can be used to get some more insight into the current power consumption of you Raspi. With
vcgencmd get_throttled
you get information whether the Raspi is currently throttled due to low voltage. An output like
throttled=0x0
indicates that currently everything is alright.
vcgencmd pmic_read_adc
provides more detailed information.
If your problem is really only the incomplete communication between the Raspi and the power supply, here are three ways to get rid of the message:
#### 1. The Clean Solution: The Official Power Supply Use the official Raspberry Pi 27W USB-C Power Supply. It’s one of the few that supports the exact 5V/5A profile. This will make the message disappear immediately, and all USB devices will receive full power.
#### 2. The Configuration Solution (Ignore the Warning & Remove the USB Limit) If you know your power supply is stable and you don’t have any power-hungry USB devices (like external hard drives without their own power supply) connected, you can manually override the check.
##### Method A: Via config.txt
Open the configuration file in the terminal:
bash
sudo joe /boot/firmware/config.txt
(For older versions: /boot/config.txt)
Add this line to the end of the file:
text
usb_max_current_enable=1
Ctrl+KX.#### Method B: Via EEPROM Configuration (Recommended) This is the most reliable method to suppress the boot warning directly at the hardware level:
sudo rpi-eeprom-config --edit
PSU_MAX_CURRENT:
PSU_MAX_CURRENT=5000
Ctrl+O, Enter, and exit with Ctrl+X.The Raspi will now “think” it has a 5A power supply.
#### 3. What happens if you only suppress the message?
If you choose the software solution but your power supply is actually weak, the following can happen:
System crashes: As soon as you plug in a USB device, the voltage drops and the Pi restarts.
Undervoltage Warnings: The small yellow lightning bolt icon (or a warning in the upper right corner) will continue to appear if the voltage drops below 4.63V.
Important for CM5 users: Here the behaviour depends heavily on the carrier board. Some boards have their own current regulation, which tricks the module into thinking there’s enough power, while others pass the CM5 warning directly through.
/dev/zram0When you install the Raspberry Pi OS that is based on Debian GNU/Linux 13 (codenamed “trixie”), it uses a device /dev/zram0 for swapping.
That device resides in memory and eats up valuable resources there (but is very fast). When your system has an SSD installed, you should consider to used a SWAP partition instead. How to setup this is explained quite well at various locations in the web.
What’s missing is how to to get rid of the /dev/zram0. There are a lot of different descriptions, especially when you ask your favourite AI, but none worked for me (at 2026-01-13). But finally I found the solution: remove the package rpi-swap (and, when you are at this point, also zram-tools), and the device is gone!
sudo apt purge rpi-swap zram-tools
sudo apt autoremove
How to setup a music server based on OwnTone is described here. This software does not only run on a Raspberry Pi, but also on various other Linux versions.
The PiJuice hat provides a UPS to the Raspberry Pi. It provides also an RTC.
If the PiJuice GUI does not start, refer to this article.
To enable the PiJuice Service that is required to configure the software, try this:
sudo systemctl status pijuice.service
sudo systemctl enable pijuice.service
sudo systemctl restart pijuice.service
From Wikipedia:
Remote Desktop Protocol (RDP) is a proprietary protocol developed by Microsoft Corporation which provides a user with a graphical interface to connect to another computer over a network connection. The user employs RDP client software for this purpose, while the other computer must run RDP server software.
[…]
Microsoft currently refers to their official RDP client software as Remote Desktop Connection, formerly “Terminal Services Client”.
The protocol is an extension of the ITU-T T.128 application sharing protocol. […]
To use the Remote Desktop Protocol (RDP) to access the Raspberry Pi computer, the server software xRDP must be installed on it:
sudo apt install xrdp
Of course on the client machine (that one that displays the Raspi’s desktop), a corresponding client software is required
/etc/xrdp/xrdp.ini – The main configuration file; usually no changes required./etc/xrdp/xrdp_keyboard.ini – The keyboard configuration.xRDPUsually this happens when the same user as for the RDP session is already logged in locally, and both are using the same window manager. In newer versions of the Raspberry Pi OS, Wayland is used instead of X11 – the latter is still used by xRDP – and as both are using different window manager implementations. Therefore it should work in most cases.