Marcus Folkesson

The Shelf - a searchable index of my board games We have a shelf in the living room that is full of board games.

Electricity price on an e-Paper display I've written before about how much the electricity price varies here in Sweden during the day [1].

Making coffee difficult Let's start this post with a video I found on Instagram [1]: I found this video incredibly fun as it reminds me of my own discussions about coffee.

memtrack and memview - tracking down memory leaks with LD_PRELOAD This time I want to share a neat application I wrote to track down memory leaks in long-running, multithreaded applications without having to recompile or relink them.

How to track down a file descriptor leak?

Rooting a VMC2040 security camera part 7: Conclusion and summary Brief In this part we are going to give some thoughts about the security of the camera and what to do to prevent this kind of attack.

Rooting a VMC2040 security camera part 6: What did work Brief In this part I will show how I finally got root access to the camera.

Rooting a VMC2040 security camera part 5: What didn't work Brief In this part I will write down the things I tried that didn't work.

Rooting a VMC2040 security camera part 4: Deeper analysis Brief This part will focus on gathering as much information as possible about the system.

Rooting a VMC2040 security camera part 3: Analyze the boot sequence Brief In this part we will go through the init script to see what (and how!)

Rooting a VMC2040 security camera part 2: Extract the firmware Brief As there were no exposed vulnerabilities via UART (no TX, only RX) or network (no open ports that could be exploited), I decided to extract the firmware from the SPINAND flash.

Rooting a VMC2040 security camera part 1: Basic examination Brief My friend had a Arlo VMC2040 security camera [1] on his shelf.

TIL - DNS queries with multiple interfaces TIL, Today I Learned, is more of a "I just figured this out: here are my notes, you may find them useful too" rather than a full blog post I must admin that I'm not one of those network gurus that knows everything

Tracing Function Calls in C with -finstrument-functions Some time ago, I wrote a blog post about mutex guards in the Linux kernel [1].

Reverse engineer a serial key validator A bit of nostalgia As many kids in my generation, I grew up with video games and the big question was always "Who is gonna be the host for the LAN party this weekend?".

Shrink disk images Brief I wanted to shrink a raw disk image file I had that contained multiple partitions.

Naming your serial ports with udev Brief UART is still a very common way to communicate with embedded systems, in fact, I would say that it is the most common way.

Remotely controlled USB hub This is no fancy project, but I thought it might be useful for someone out there.

GNSS spoofing using SDR First of all, sending false GNSS signals on the air is illegal in most countries.

Using AI to write me a tool Brief This is my first attempt at using claude-sonnet-4.5 to help me write code using Github copilot.

Using socat to bridge interfaces Brief Whenever it comes to connecting two interfaces together on Linux, socat is my go-to tool.

I2C Bus Recovery Brief I was working on a project where we had a problem with an I2C bus that was sporadically hanging during communication with a certain device.

What to expect When working in Linux, you’ve probably come across commands that require interactive input — things like typing a password or confirming the same prompt over and over again.

Repair of my Fluke 179 multimeter My belowed Fluke 179 multimeter suddenly stopped working.

Running mtest with U-Boot Memory is, of course, a very important part of any embedded system.

Determine wakeup cause (ACPI) I had a problem with my laptop to enter suspend mode, when I ran systemctl suspend it would just wake up immediately.

An attempt to learn blindfolded chess This is one of my more unusual projects, but I still think it is worth sharing.

Lets talk about ECC and NAND flashes Raw NAND flashes are not that common these days.

Repair of Sennheiser Momentum True Wireless earbuds I have a pair of Sennheiser Momentum True Wireless (MTW3) earbuds that had been lost for a while.

Don't forget the Jira tag in your git message I keep forgetting to add the Jira tag in my git messages.

Control of my geothermal heat pump The electicity price in Sweden varies a lot during the day.

UBI volumes in Yocto These days, managed NAND flash memories such as eMMC or SD-cards has become more common in the embedded Linux systems as they abstract (or hide..) the complicated raw NAND memory under the hood.

Remoteproc, rpmsg and SYSBIOS I'm currently working with a couple of SoCs (OMAPL-138, DRA7xx) from Texas Instruments where both has an C6xx DSP core along with the ARM core.

Detect time jumps in Linux Recently I had a case where the application created multiple timers for different events.

TIL - suid_dumpable TIL, Today I Learned, is more of a "I just figured this out: here are my notes, you may find them useful too" rather than a full blog post Ever notice that you can't get a coredump from a process running with extra privileges like capa…

Protected FIFOs and regular files Since version 4.19 [1], Linux has the default behaviour to prevent opening of regular files and FIFOs that is not owned by the user in world writable sticky directories.

Restoring a power hammer I have bought myself a power hammer - something that I have wanted for a long time.

Writing a clocksource driver for Linux Today we are going to write a clocksource [1] driver for Linux!

Writing a UART driver for Linux Today we are going to write a UART driver for Linux!

Include code from a file with Hugo First of all, all credit goes to Marcus Olsson [1] who pretty much wrote this Hugo Shortcode [2] which I only have made some small changes to.

TIL - make pacman-pkg TIL, Today I Learned, is more of a "I just figured this out: here are my notes, you may find them useful too" rather than a full blog post v6.11 of the upstream kernel makes it really easy to do kernel devlopment on Arch Linux with t…

"You are the primary manager for this project" Yes I'm.

Restrictions that comes with capabilities I debugged an interesting problem this weekend related to which impact capabilities could have on a running process in a Linux system.

TIL - strace and capabilities TIL, Today I Learned, is more of a "I just figured this out: here are my notes, you may find them useful too" rather than a full blog post strace [1] is a terrific tool to trace system calls and signals for a specific command.

TIL - interactive shell script TIL, Today I Learned, is more of a "I just figured this out: here are my notes, you may find them useful too" rather than a full blog post Tody I saw this line in a script: 1INTERACTIVE="" && [[ -t 0 ]] && INTERACTIVE="-it"…

Board bring-up part 4: Wrap it up I'm currently working with a board bring up for a custom hardware based on a OMAPL138 from Texas Instruments.

Board bring-up part 3: Other peripherals I'm currently working with a board bring up for a custom hardware based on a OMAPL138 from Texas Instruments.

Board bring-up part 2: NAND flash I'm currently working with a board bring up for a custom hardware based on a OMAPL138 from Texas Instruments.

Board bring-up part 1: Memory hassle I'm currently working with a board bring up for a custom hardware based on a OMAPL138 from Texas Instruments.

Forge a kitchen knife Another attempt to forge a knife.