Recent content on feldspaten
This procedure might brick your device. Proceed with caution, you have been warned. 
 EDIT: This procedure has been updated on 2026-08-11 given the helpful feedback of helpful people which was helpful. 
 If you are confused by the whole key nomenclature in UEFI, go and see this excellent blog post for a summary of the different UEFI key types. In this guide we need three key types: The…
Assuming one has an old Yubikey, that needs to be disposed. The Yubikey contained some sensitive key material and you want to be sure nobody every could access it.
For the record: Modern Yubikeys have a factory reset function, but we’re not in here for the easy way. We want to do it properly. By using an adequate amount of violence. 
 Stage 1: Using violence
 Okay, long story…
In this post we go through the steps to create your own personal Certificate Authority (CA) from scratch using only openssl . 
This can be useful for your own homelab or your own server in a local LAN.
Intentionally the design is simplified and we omit more advanced things like intermediate certificates . 
 We use rsa because my first experiments with ed25519 failed at the time of…
We all know that Kindles are evil, and Amazon tracks everything what you read and bla bla bla … But this story really shows how much they collect about you. 
 A friend of mine published recently a book and shared an interesting screenshot of the Kindle Direct Publishing page.
The screenshot shows a dashboard with a field on many pages of the book have been read in the last…
Imagine the following: You’re stuck at a Telescope site. You have some off time, and it’s cold outside. Like really cold. You need to sustain your body weight. All you have are the ingredients listed below and your only chance of survival is to make a delicious Tiramisù. This exact situation has arised during my HESS shift in Namibia, when we have been forced to improvise Waffels…
Fossil based mobility was our biggest individual CO2 footprint, and with our new amazing electric car, this is now a thing of the past. Electric cars are better for the environment . 
 For me the most amazing part is a triviality: The fact that you can charge your car at home. We went for a small drive today when possible (the weather conditions are currently challenging) and drove the battery…
Happy new year fellas! 
 As part of the new year’s cleanup procedures, this blog now runs on openSUSE Leap 16 and I hope it will for the next years to come. 
 Leap 16 is a new codestream, so it deserves a complete new installation. I’m still fixing some issues with SELinux, some missing packages and new configuration schemas, but overall things are already working quite nicely.…
There’s a known issue with Civilization 5 on Linux, where it randomly crashes with a segfault. On Reddit the issue is discussed and the proposed solution is to limit the number of simultaneous threads to 8 or below. 
 On my system I found that this was already the case and further lowering it to 4 reduced the number of crashes (but they never went fully away) while the game seems to…
As a follow-up of my previous adventure on getting FreeBSD 14.3 running on the CM4 - Forget about FreeBSD 14, just use FreeBSD 15. It works out of the box. 
 SATA disks
 One issue was with the SATA Controller of the Turing Pi though, but luckily this forum post already resolved the issue for me. 
 So, when botting I noticed that the external SATA HDD was not recognised and I saw…
Holy moly, it works! Pre-generated assets are at the end of the post. 
 After yesterday’s openSUSE Leap 16.0 Release (yay!) and because I’m still too sore to go for my usual Thursday run, I took this evening to get openSUSE Leap 16.0 working on a Turing RK 1 . Thursday evenings are my me time, and I’m glad I could make this work in one sitting! 
 The main problem was,…
Update - Just use FreeBSD 15 - it just works! 
 I’m in the process to modernize our very much aging backup machine. Instead of spending about 300 bucks on new hardware, I want to get it running on hardware that I already have - and what I have is a Turing Pi and a Raspberry Pi Compute Module 4 (8 GiB). The Turing Pi has two SATA ports for Node 3, which are just about perfect for what I…
Last week I was in the UK and the UK mobile network is … weird. 
 I have no idea but for some reason on SOME of the cell towers I didn’t had connectivity without VPN. 
 
 My wife has the same carrier as I have and didn’t encounter those issues. Also, it’s not everywhere, it’s just on some of the cell towers. I didn’t had noticeable issues while…
This is a custom recipe I made for a little friend of mine, who cannot have eggs. It’s just a simple lemon yogurt cake with semolina and no eggs. 
 250g flour
100g semolina
100g sugar
350g greek yogurt
100g vegetable oil
1 package vanilla sugar
1 package baking powder
1 Lemon
 Optional: Add 100g sugar more, if you like the case to be sweet. We prefer them…
Signal Proxy allows users in countries who are subject to network limitations and censorship to connect to the Signal network via a Proxy server. The idea is simple: Any government cannot reliably censor a horde of volunteers who spin up a swarm of proxies. This decentralization allows to create a horde of small targets, too small and numerous for any state actor to reliably go against. It was for…
Over the last decade, NetworkManager has become one of the most widespread network managing solution.
Only recently I managed to get my own homelab setup for one of my hypervisors with bonds, vlans and bridges working. Network Bonds to establish backup links, over which I have a default bridge and two separated network bridge adapters, both on their own VLAN. Like this I can transparently…
I recently found a handful of coins on the parking lot of our supermarket. Nothing big, just a few coins all below 50 cents. Since in the Netherlands almost all money transactions are done digital, I have one of those wallets that doesn’t contain a pocket for coins anymore. I typically still carry some loose coins in that small little pocket in my jeans (if I wear jeans) and so I just put…
Last winter season was the first season for our new heatpump in our permanent home. The first season was more of a stress test for the heatpump, as our roof isolation was not present, and much of the heating energy was wasted. This year was expensive and hopefully not representative for the years to come. 
 Winter season 2024
 For this and future measurements I will consider the winter…
Restic is a mature, effective and secure backup solution that covers a wide range of use cases. I use it heavily for all of my backups. The program itself is peak open source: it’s free (as in BSD-2-Clause license), runs on any modern OS, runs on systems low on resources and it can be learned in 30 minutes by reading the well-written documentation . It provides almost everything you need.…
Just a quick shoutout to the Dutch weather provider KNMI, who open sourced the official Android App plus Infrastructure on Gitlab . 
 The Koninklijk Nederlands Meteorologisch Instituut (royal Dutch metrological institute) is a scientific institute of the Dutch government responsible for weather, climate and seismology. Clarification: They are responsible for monitoring the weather, not for…
I recently discovered Nepenthes , a tarpit for LLM web crawlers. It’s essentially a reverse Slowloris that spits out markov-chain nonsense. A nice way to catch unwanted guests and feed them what they are searching for. 
 I had my fair share with those nasty LLM crawlers and so I setup my own tarpit . The robots.txt file disallows everything, so unless you are not respecting the big STOP…
Welcome to the year 12025 human era. For me this will be the year of less. 
 Last year was intensive. We got a child, our own house, we did renovations, work also got more intensive, we moved, we learned to live with a kid and it felt like a constant run against the clock to get the thousand different things somehow sorted.
It was worth it for sure, but it was costing a lot of energy. Last…
… or at least more upstream . 
 Recently I tried to migrate our home NAS from our good old (TM) Intel Celeron N3150 to a more modern Radxa Rock 5 ITX . The new board fits perfectly to the needs of our home: Small, enough peripherals for what I need, low-power yet strong enough to host our home services on it for the next years to come. And it doesn’t cost an arm and a leg,…
Multiple online sources report that Microsoft claims Recall to be an opt-in experience and you can remove it . I cannot find any direct article from Microsoft itself, but there are others confirming it with direct references to Microsoft spokepeople. 
 I have my doubts that this will age well, and that’s why I’m posting this here. In a typical Microsoft move we will first see it…
Fascism isn’t knocking on the door with a “hello, I’m fascism, please empower me”. 
Fascism knocks on your door with “this person over there steals your butter. Vote for me, I will make sure they’re not going to have any more butter on their bread”. 
 Fascism is subtile until it isn’t. And then it’s probably too late. 
 #fuckfascism…
Mqtt is a lightweight publish-subscriber protocol for message queues, typically used with IoT devices, but also for monitoring services. As such, messages have typically a ephemeral character. I use several Zigbee sensors together with zigbee2mqtt in our house and I wanted to collect and store all the mqtt messages in a database to keep track of what’s going on. In this blog post I describe…
Life goal unlocked: Living in our own home. 
 We recently did the move to our new permanent home in the beautiful town on Nuenen. The move was a bit chaotic and the last months have been quite an experience. But that lies in the past, we’re still living between the boxes and there are many things still to be done in our home. But we have a place that we can call our own. Achievement…
Please, don’t spam my forgejo instance. 
 Someone is trying to pull stuff from non-existing repositories from my forgejo instance and puts a significant load onto my server. 
 No hard feelings, please just check your bots 🙂 I don’t log IP addresses per request and would like to keep it that way. Thank you! 

How does it look when your database is starved from memory and runs into trouble? 
 Recently feldspaten moved to a ARM server and by doing so, I drastically reduced the amount of system resources.
Previously I rented a dedicated root server, which was certainly overkill and I didn’t see the need for it anymore. Servers just got so powerful that renting the fraction of one is just…
Peter Fouché, a combat medic and founder of the charitable organization project Konstantin has died on the 27. June from a Russian sharpnel while trying to save lifes.
 The BBC rightfully writes he “has died like a hero in the battlefield”. 
 
 RIP Peter Fouché, you have been so much more than I could ever be 🫡. 

An excellent summary of the benefits of “A"I: I Will Fucking Piledrive You If You Mention AI Again . 

feldspaten.org runs now on a much more resource-friendly ARM-Ampera based cloud instance on Hetnzer.
Previously I had dedicated root server, which made sense for the time being. But nowadays the cloud offerings are economical and powerful enough to fulfil all of my needs. Storage is still a bit expensive, but it’s still cheaper than a dedicated root server for what I use. 
 Since I…
podmansh executes a login shell within a podman container and allows you to have a containerized platform for users to login. It’s documentation relies on Quadlet provided containers, which is great in general, but comes with one caveat: Containers are ephemeral. I wanted to have a custom sandbox for my user, where I can get even local root, but because everything is contained in a…
I got a Samsung 990 Pro NVME SSD, which by default reports a blocksize of 512B. The purpose of this device is to host virtual machine workloads on the zfs filesystem. Because of performance and replication considerations I was wondering, if switching from 512B to 4k blocksize (as used in most modern HDD) would result in a performance impact, so I ran some simulations. 
 TLDR: Stick with the…
Recently I expected a package from UPS from a domestic provider. In the course of this delivery I got two scam SMS, the first just hours after a SMS from UPS about a pending delivery.
Based on the close proximity to an actual delivery times and the received text messages on my phone, I find it hard to believe this was a coincidence. 
 A short murder mystery story. 
 What happened
…
Plasma 6 lands in openSUSE Tumbleweed and it’s awesome! 
 
 Overall it works really nice. There are some small issues, I filed some smaller bugs, but overall the transition went rather smooth - knowing that the graphical system would crash during installation from a friend - I just installed it via text console. 
 Plasma 6 uses Wayland and it works better now than the last time I…
I find RISC-V an interesting architecture as a truly open hardware platform. Maybe at some point in the future this platform might run on our desktop and server systems. For RISC-V as a non-microcontroller, i.e. a “real computer”, it’s still early days and I wanted to get started with testing openSUSE on it. So recently I purchased a Milk-V CM to get started. Unfortunately there…
I love Free Software because it empowers people and allows them to use, repair and maintain devices beyond an arbitrary defined lifespan.
Free software helps to reduce e-waste and to conserve energy-intensive resources on our already burning planet #ilovefs #ilovefreesoftwareday 

Note: In an older version of this article, some of the things stated here were wrong. Sorry for that. 
 I recently played with my Yubikey to establish them as second factor for my ssh keys.
The process is straight-forward, however it took me some time to go through Yubico’s documentation. Here I write the process down in my own words. 
 ssh public key authentication can be…

 
 Immutability done right. 

 
 Since our little one is born, I have little-to-no spare time anymore to do proper server maintenance. Luckily I was prepared for this, and automated as much of the recurring tasks that I could. This post is a praise of our openSUSE transactional systems (Leap, Leap-Micro, MicroOS, Tumbleweed), because they make my life as a spare time home and…
I’m happy to announce that last week our first child was born. We’re more than happy and I’m now on parental leave for some time. 
 We’re super happy and excited and tired and everything! This is so far the proudest achievement and most important thing in my life.
It also feels like a big milestone. Things have changed, and I believe they have changed for the…
Sorry for the outage last week. I did a domain transfer and it didn’t went as smooth as I hoped for. It took my new hoster some time to fix an internal nameserver issue. 
 I’m still puzzled why this transfer went haywire. I did a couple of transfers in the last months and all of them went smoothly. Only the most important domain then screwed up. Well, I guess that’s just…
Today we had a rare guest in our small little garden: A wild sparrowhawk explored the area. We have a small little bird feeding house, well visited during the winter times when we supply food for the local birds, so the motivation for the visit was supposedly a hungry stomach. All little birds have been gone, so sadly for the young sparrowhawk our garden did not offer the feast, it hoped for.…