Taming the Virtual Hydra: Troubleshooting VirtualBox on NixOS

What started as a quick VirtualBox install turned into a multi‑headed boss fight: USB errors, a sulking kernel driver, a turf war with KVM, and even a Nix syntax bite. Here’s the complete journey and the fixes that finally made my VM boot. Head #1 — USB devices wouldn’t enumerate Can't enumerate USB devices Could not load the Host USB Proxy service: VERR_NOT_FOUND Root cause: Host USB support + Extension Pack missing, and the user not in vboxusers. ...

August 24, 2025 · SarCoptU

NixOS Cheatsheet

If you’ve ever felt overwhelmed by NixOS commands, flakes, or the dreaded garbage collection panic, this guide is for you. It’s not just a cheatsheet—it’s a practical survival kit for running NixOS with flakes, keeping your system clean, and always having a rollback strategy when things go sideways. 🖥️ NixOS Essentials Task Command Show version nixos-version Edit config (classic) sudo nano /etc/nixos/configuration.nix Rebuild + switch sudo nixos-rebuild switch Build only (no switch) sudo nixos-rebuild build Roll back last rebuild sudo nixos-rebuild switch --rollback List generations sudo nix-env --list-generations --profile /nix/var/nix/profiles/system ⚡ Flakes Basics Task Command Init flake nix flake init -t templates#nixos Show flake outputs nix flake show Update all inputs nix flake update --commit-lock-file Update one input nix flake lock --update-input nixpkgs --commit-lock-file Build system sudo nixos-rebuild build --flake .#<hostname> Switch system sudo nixos-rebuild switch --flake .#<hostname> Boot (safe) sudo nixos-rebuild boot --flake .#<hostname> 🔄 Safe Updates & Rollbacks Keeping your system updated is great… until it doesn’t boot. Here’s how to avoid disasters. ...

August 24, 2025 · SarCoptU

Dual‑Boot: Windows 11 + NixOS (with Flakes)

For ages I wanted a clean dual‑boot between Windows 11 (for the few things that require it) and NixOS (for everything I actually enjoy). This is the full journey: GParted wizardry, fixing MBR/GPT issues, laying out a big EFI (because NixOS loves EFI space), and finishing with flakes. Step 1 — Disk Layout in GParted I booted a live USB with GParted and created the following: EFI System Partition (ESP): 1030 MB, FAT32, flags boot, esp Windows: 200 GB, NTFS Linux swap: 8 GB Linux root: rest of the disk (later Btrfs) Why a big ESP? NixOS + systemd‑boot keeps multiple generations of kernels/initrds. A tiny 100 MB ESP fills up fast. ...

August 23, 2025 · SarCoptU

SSH Connect to a Kali Virtual Machine in Virtualbox

Kali is a great learning tool for learning cybersecurity, especially the red-attacking side of it. For the longest time, I had trouble running the Kali VM on my rather old Thinkpad X1 Carbon, as the image consumes quite a few resources. There is a way to use most of Kali’s tools with little resource consumption: ssh into the image via your distro terminal. It turns out it’s quite easy to set this up in VirtualBox, as described in this article: ...

January 13, 2024 · SarCoptU

Make Debian 12 Pretty and Useful

There are a few customisations I have come to love on the personal Debian install. This blog post is meant to describe the steps for my ideal (at this point) Debian 12 post-installation cleanup and provide a few security applications for everyday use and a few programs for light security work. Download and Install Debian 12 Download the DVD version for 64-bit PC architecture from here: https://cdimage.debian.org/debian-cd/current/amd64/iso-dvd/ Installation-wise, I chose to install the Gnome and nothing else: ...

November 27, 2023 · SarCoptU

Thinking About Computing Needs

After spending days trying to optimise my setup and thinking about the perfect use of my current hardware and also trying to get rid of stuff I don’t use, I came to the conclusion I need more hardware. This is kinda concerning, considering the initial problem I had before all this was that I have too much stuff around. This might have been influenced by watching The Minimalists – Less is Now or John Hammond’s video for his one laptop setup for teaching cybersecurity. ...

February 15, 2022 · SarCoptU

Raspberry Pi NAS with Open Media Vault and Plex

Ingredients: Raspberry pi 4 – I used one with 8Gb of RAM with whatever case is available 1 or 2 external hard disk drives (HDDs) – if 2 are used, a powered USB hub is required, as the pi does not provide enough power for more than 1 HDD of note also, no RAID configurations are possible with external, USB connected HDDs USB microSD card adaptor for installing Raspberry Pi OS raspberry pi power plug cables: USB for HDDs, internet cable with RJ45 plugs Ingredients Step 1: Install Raspberry Pi OS Download the Raspberry Pi imager from https://www.raspberrypi.com/software/ and select the image to be installed on the Pi. ...

January 31, 2022 · SarCoptU

Xubuntu with AwesomeWM

After some looking about and being sick of running Windows 10 just for doing some Scratch-like programming for uni, I have decided to update my system to full a Linux pc with, if needed Win10 and Kali VMs for all my HackTheBox and TryHackMe needs. Because I still don’t have proper internet and using phone internet sharing, installing arch without some cable internet is a bit of a stretch. After seeing some Debian-Titus work in progress during ChrisTitusTech stream, I definitely want to give AwesomeWM a try. What’s not to like about a small, quick and efficient window manager. ...

December 15, 2021 · SarCoptU

CompTIA Security + Study Notes: Cryptography

Cryptography is as old as the desire of humans to communicate secretly. A famous example is that of the so-called Caesar cypher, named after Julius Caesar. He used to encrypt his correspondence by shifting the letters of the alphabet to the right or left an agreed-upon number of spaces. Cypher disc Image Credit: Cypher disc By Hubert Berberich (HubiB) – Own work, Public Domain, https://commons.wikimedia.org/w/index.php ...

August 20, 2021 · SarCoptU

Network + Study Notes: Open System Interconnection (OSI) Network Model

Computers have a very particular way of communicating with each other. For example, before widespread computer networks and the internet, people shared files by “sneakernet”: wearing a comfortable pair of sneakers and putting the info on the storage media and travelling to the destination computer to copy the data. This is not a very effective way to share files, and large companies soon realised this was a huge market and started developing various network protocols. The problem was that many of these protocols were proprietary and incompatible with each other. ...

June 13, 2021 · SarCoptU