op-co.de blog
This post is about setting up and configuring a dnsmasq container on a MikroTik RouterOS device to be used as an authoritative DNS server and a forwarding cache at the same time. Introduction Recently I joined DN42 , a world-wide overlay network created for experimenting with IP routing and for connecting communities, hack-spaces, and networking nerds who are not allowed 😜 to break the real…
So I was bored and I set up an XMPP server under 👆️.op-co.de , in addition to the one I already had under ツ.op-co.de . It worked with some clients and failed with others. But both ツ and 👆️ are valid Unicode 1.1 characters, so WTF? Buckle up (or better: put on your 🤿) for the 19-RFC deep dive... ...or skip right to the TL;DR . Note: despite my generous use of Emojis throughout this post, none of…
For my time-lapse photography , I'm using darktable to develop the pictures, processing hundreds, sometimes over a thousand, RAW photos for a single scene. Often, getting a good result requires multiple iterations of export and video rendering, with each export usually taking half an hour or longer on my slightly dated PC. With OpenCL, exports can be significantly accelerated if the workload fits…
This is a follow-up to the Samsung NX mini (M7MU) firmware reverse-engineering series. This part is about the proprietary LZSS compression used for the code sections in the firmware of Samsung NX mini, NX3000/NX3300 and Galaxy K Zoom. The post is documenting the step-by-step discovery process, in order to show how an unknown compression algorithm can be analyzed. The discovery process was…
This post documents how to convert a directory full of project release ZIP files into a git history with better diffs and commit dates. It was an itch I needed to scratch and there is no reason to keep the hacky tooling to myself. The NX-KS project I'm an active user of the NX-KS2 mod on my 2014 Samsung NX500 camera. The mod implements additional functionality and offers an UI overlay to access…
In 2014 and 2015, Samsung released the NX mini and NX3000/NX3300 cameras as part of their mirrorless camera line-up. My 2023 archaeological expedition showed that they use the Fujitsu M7MU SoC , which also powers the camera in the dual-SoC Exynos+M7MU Galaxy K-Zoom . This blog post performs a detailed step-by-step reverse engineering of the firmware file format. It is followed by…
APRSdroid is an Amateur Radio geo-location ( APRS ) app for Android licensed under the GPL. It started as a Scala learning experience at New Year's eve 2009. This post is a review of 15 years of the project and related developments in the ham radio world. There is also the two-year recap of the app and the Scala on Android experience that I wrote in 2011 . The evolution of APRSdroid In 2009, when…
Running a colo / hosted server with Full Disk Encryption (FDE) requires logging in remotely during initramfs, to unlock LUKS. The usual setup tutorials run Dropbear on a different port, to prevent a host key mismatch between OpenSSH and Dropbear, and the scary MitM warning it implies. However, it's much cleaner and nicer to share the same host key between Dropbear during boot-up and OpenSSH during…
Exactly one year ago, after updating a bunch of Debian packages, my laptop stopped booting Linux. Instead, it briefly showed the GRUB banner, then rebooted into the BIOS setup. On every startup. Reproducibly. Last Friday 13th, I was bitten by this bug again, on a machine running Kali Linux, and had to spend an extra hour at work to fix it. TL;DR: the GRUB config got extended with a call to fwsetup…
In 2013, Samsung released the Galaxy NX (EK-GN100, EK-GN120, internal name "Galaxy U"), half Android smartphone, half interchangeable lens camera with a 20.3MP APS-C sensor, as part of the NX lineup that I analyzed last year . A decade later, the Galaxy NX is an expensive rarity on the used market. Luckily, I was able to obtain one of these Android+Linux-SoC hybrids, and will find out what makes…