Blog

Minimal Ubuntu Installation with debootstrap

September 17, 2021

I dislike the new Ubuntu installer, subiquity.

Apparently I wanted to do something that was not supported by this new installer (yes, I know there’s an encrypted LVM variant but I didn’t want LVM). And even when I installed the minimal possible package selection, I found myself writing a cleanup script just to remove unwanted packages afterwards.

There may be another guide coming soon on how to convert an existing Ubuntu Server installation into a fully encrypted one, which unlocks automatically on boot through network-bound disk encryption. However, this is a guide on installing a custom Ubuntu server with an encrypted root on a UEFI system using debootstrap – the “hard” way.

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Tinkering with an ESP32-C3 module

September 3, 2021

There was a Hackaday article in February titled “The RISC-V ESP32-C3 will be your new ESP8266”. Well, after being frustrated with the small memory on an ESP8266 board just recently, I was eager to try this new part. So I ordered some modules and a development board by Ai-Thinker from Aliexpress.

Modules #

What I liked most about this part on first sight was the fact that it has builtin USB, like its bigger sibling the ESP32-S2! That is not a fully-featured and reporgrammable endpoint but it provides a serial console and JTAG connection – enough to program and debug your chip without an external USB-to-Serial chip! There’s lots more to like, of course: it’s a RISC-V part and includes both WiFi and Bluetooth.

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Create squashfs archive from stdin and sign it on-the-fly

May 8, 2021
Linux, Network

The use-case might be a little specific but I’ll describe it nonetheless, hoping it may help someone. A while ago I read Practical Forensic Imaging by Bruce Nikkel and tried out the sfsimage script that he presented therein.

The idea is as simple as it is brilliant: combine open-source disk recovery tools like dc3dd with the great compression and usability of readonly squashfs filesystems. The imaged disk is piped directly into a virtual file inside the archive and some metadata of the acquisition is added alongside it to create a “forensic image”. This image can be mounted and inspected without elevated privileges using squashfuse – all the while usually only taking a fraction of the original disk size.

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Ein Fuchs muss tun was ein Fuchs tun muss.

February 18, 2021
Diy

This is just a simple post about some artwork I did as a present recently. I wanted to try my hand at freeforming solder-art, so I got some brass rods and tried to form a foxes head.

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Noritake Itron VFD

October 21, 2020

After finishing my own VFD clock project a while ago, I now bought a ready-made module from Noritake Itron because I wanted to take a look how they do it – especially the filament supply.

These modules usually sell for somewhere above 50€. But here I found one on eBay for just over 20€. The description had no model number or dimensions but I didn’t care much .. I bought it. Well, what should I say .. this module is huge:

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Behelfs-Mund-Nasen-Maske nähen

March 27, 2020
Diy, Sewing

Aktuell verbreitet sich das neuartige Coronavirus (SARS-CoV-2) rasant auf der gesamten Welt mit teils verheerenden Folgen. Dies soll aber kein Beitrag über das Virus an sich sein, sondern eine Anleitung wie ihr euch auch in Zeiten, in denen Mundschutz Mangelware ist und besser dem medizinischen Personal vorbehalten werden sollte, ganz einfach selber eine Behelfslösung nähen könnt.

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VFD Tube Experiments

February 10, 2020
Electronics, Vfd, Arduino

Vacuum flourescent displays are a beautiful piece of retro technology. Noritake Itron and a few others still build them as dot-matrix or full graphic displays. But the technology dates back to the 70’s and you can find some surplus units available on eBay.

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Flash Arduino without a Bootloader from a Raspberry Pi

November 6, 2019
Linux, Electronics, Arduino

To keep things short: I’ve had an Anet A8 3D printer for a while now and wanted to flash an updated version of its Marlin firmware. For some reason however, the bootloader was broken. So I couldn’t flash it with avrdude by simply using a USB cable. For this case you can find lots of tutorials on how to flash Arduino boards with a second Arduino. I didn’t have a second Arduino at the time though … so why not just bit-bang it from a Raspberry Pi instead?

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