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330 votes
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What is rpikernelhack?

"rpikernelhack" is a fake package name and a directory name used as part of a hack (in the sense of a dirty but expedient solution to a problem) to work around the fact that the Raspberry Pi ...
Peter Green's user avatar
  • 6,486
53 votes

What is rpikernelhack?

It's just the directory name given by the developers who have created a Raspberry Pi specific set of patches to the Linux kernel. It is a fix by the Raspbian developers to fix a FAT file-system ...
Rebroad's user avatar
  • 665
16 votes
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Pending kernel upgrade even after reboot my RPi4

Mixing @Dougie 's comment above and this post: https://www.raspberrypi.org/forums/viewtopic.php?t=270251&p=1639417 the v8 kernel is experimental and should not be used needrestart is confused by ...
Olivier's user avatar
  • 431
14 votes
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Control GPIO pins from C

sysfs has been deprecated and has been replaced with libgpiod. https://www.beyondlogic.org/an-introduction-to-chardev-gpio-and-libgpiod-on-the-raspberry-pi/ The interactions are with /dev/gpiochipx ...
joan's user avatar
  • 71.1k
14 votes
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How to revert from rpi-update to stable build

"In normal circumstances there is NEVER a need to run rpi-update as it always gets you to the leading edge firmware and kernel and because that may be a testing version it could leave your RPi ...
Milliways's user avatar
  • 60.3k
14 votes

kernel types in Raspbian 10 - Buster

kernel.img is 32-bit for BCM2835 (RPi1 & Zero) kernel7.img is 32-bit for BCM2836 (RPi2) and BCM2837 (RPi3) kernel7l.img is 32-bit for BCM2711 (RPi4) kernel8.img is 64-bit for BCM2837 (RPi3) or ...
Dougie's user avatar
  • 5,321
13 votes
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failed to start udev kernel device manager

It might be interesting to know which version you are running, and if you happened to update packages recently. I encountered a similar error message on my raspberry pi2 after upgrading to raspbian ...
EThome's user avatar
  • 146
11 votes
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iptables: nat table does not exist

Quick guess: You've upgraded the OS and the system has been up for a very long time, or managed to upgrade it without replacing the kernel, because the 4.4.11-v7+ modules have already been removed ...
goldilocks's user avatar
  • 59.1k
10 votes
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How does the pi know which kernel to load?

All the boot magic is in /boot/config.txt. kernel: The alternative filename on the boot partition to use when loading the kernel; the default value is kernel.img. from official documentation ...
SiKing's user avatar
  • 347
8 votes
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Does Raspbian's `/proc/config.gz` contain the running kernel's settings?

Yes; /proc/config.gz, if it exists, always refers to the running kernel's configuration (but see the last few paragraph below) since procfs, like sysfs and devtmpfs, which are used to implement the ...
goldilocks's user avatar
  • 59.1k
8 votes

End kernel panic not syncing cannot allocate swiotlb buffer and cannot provide with dma bouncer buffer

I ran into this same issue with a new install of Pi OS after setting the GPU memory to 896 MB in raspi-config. To fix it without reinstalling: Put the SD card in another computer that can read the &...
Cole P's user avatar
  • 81
7 votes
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Raspberry Pi cannot create temp file for here-document: No space left on device

Run the command sudo raspi-config and select the Expand Filesystem option. Then you should be good to go.
Patrick Cook's user avatar
  • 6,365
7 votes

How compile a loadable kernel module without recompiling kernel

There is a much simpler version here, tested on jessie and stretch. sudo apt-get install raspberrypi-kernel-headers and then when your files are in place : make -C /lib/modules/$(uname -r)/build M=...
pim's user avatar
  • 622
7 votes

Pi 3 Raspbian "stretch" (testing) disables wifi

The package that provides the Wi-Fi firmware is called firmware-brcm80211. To downgrade this package to a version that works: sudo apt-get install firmware-brcm80211=0.43+rpi5 To prevent this ...
NobodyNada's user avatar
7 votes

failed to start udev kernel device manager

As of systemd 235-2 this still continues with the exact same error. For people landing here from google: If you see that after apt dist-upgrade that either udev, journald or even timesyncd are ...
wadge's user avatar
  • 171
6 votes

Raspberry Pi 1 Model B+ end of life?

The rainbow square is an under-voltage warning. You might consider upgrading to a more powerful power supply (more amps, not more volts). EDIT To further answer your question I have tried to ...
88weighed's user avatar
  • 905
6 votes

Wireguard "Unknown device type" "Protocol not supported"

According to a comment on r/Wireguard, this error is caused by having the wrong kernel headers: dkms packages (wireguard-dkms this time) need kernel headers for current kernel you have loaded (uname -...
ki9's user avatar
  • 295
6 votes

raspberry pi 4B no /dev/spidev0.0

By default, Raspberry Pi installations do not normally enable the SPI functions. Without SPI being enabled, the /dev/spidev0.0 inode is not created. This procedure is taken from https://pimylifeup.com/...
cmm's user avatar
  • 161
5 votes

Where do I find the linux headers for an image?

See answer here https://www.raspberrypi.org/forums/viewtopic.php?f=91&t=154749 You can try sudo apt-get install raspberrypi-kernel-headers if you're running raspbian.
Dip's user avatar
  • 111
5 votes
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How can I troubleshoot kernel panics?

Is there a way to view the entire logs...? Your Raspberry Pi typically has a serial console enabled (or can be configured to have a serial console) on one of the built-in UARTs, exposed on GPIO pins ...
larsks's user avatar
  • 653
4 votes

How to change the default governor?

I made a small programm to change it and let it be changed every boot by automatically creating an init.d script. Link to my project
MeisterD's user avatar
4 votes

How to use the perf utility on raspbian?

I was able to install the perf package using sudo apt-get install linux-perf-4.9. Use uname-r to find your kernel version, and apt-cache search linux-tools to find the proper package name.
Josh Peterson's user avatar
4 votes

Linux headers generic package not found

Run below command on the terminal to install sudo apt install raspberrypi-kernel-headers
Vijay Panchal's user avatar
4 votes
Accepted

Is it possible to run Raspberry Pi 3 with a 64-bit kernel and 32-bit user space?

Is it possible to run Raspberry Pi 3 with a 64-bit kernel and 32-bit user space? Yes. Some pre-built images have this ready to go: Crazyhead90's Raspbian Stretch Lite and Desktop 64-bit images (Pi 3,...
jdonald's user avatar
  • 2,914
4 votes
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What does mkknlimg exactly do, and what is a trailer?

It's just a blob of data at the end of the kernel image. Observe: # knlinfo /boot/kernel7.img Kernel trailer found at 4222224/0x406d10: KVer: "Linux version 4.4.8-v7+ (dc4@dc4-XPS13-9333) (gcc ...
JayEye's user avatar
  • 1,898
4 votes

Check system name and kernel version in script

Here's something which takes a different twist on /etc/os-release, which has a standardized format based around setting shell variables, meaning you can source it and use them. First have a look at ...
goldilocks's user avatar
  • 59.1k
4 votes

How to boot raspberry pi very quickly into Linux?

You can build linux from scratch on the pi (http://www.intestinate.com/pilfs/guide.html). With a custom kernel, you can boot into systemd in < 1s.
Brian's user avatar
  • 141
4 votes
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Installed kernel headers and $(uname -r) differ

You can restore your system to standard with sudo apt-get update && sudo apt-get install --reinstall raspberrypi-bootloader raspberrypi-kernel sudo apt-get install raspberrypi-kernel-headers ...
Milliways's user avatar
  • 60.3k
4 votes

My Adafruit PITFT stops working after sudo apt-get update

Per the Adafruit Help! FAQ: Doing an apt-get upgrade or rpi-update will blow away the custom PiTFT kernel. You will have to reinstall the kernel. If you had already made a working PiTFT setup, ...
Steve Robillard's user avatar
4 votes

How can I troubleshoot kernel panics?

Addressing Point 2 ...and how do I troublshoot kernel panics? A kernel panic is just a crash inside the kernel. A crash caused by any number of normal software or hardware faults. Debugging the ...
crasic's user avatar
  • 3,003

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