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About.

Who I am

I am Alex, an engineer based in Greece. I have been taking systems apart and putting them back together since 2011. It started with a PS2 console mod, which taught me that I genuinely enjoy understanding how machines work at the lowest level. Shortly after, I got my hands on a Samsung Galaxy S2 (I9100) and ran straight into the infamous eMMC brickbug. Instead of walking away, I dug into the storage firmware, figured out the root cause, and contributed a fix. That experience set the direction for everything that followed.

Since then I have spent over a decade in the Android and Linux ecosystem: building and optimizing custom ROMs, writing and tuning kernels, tweaking framework internals, optimizing drivers and firmwares for performance and battery life. I care about efficiency, scalability, and maintainability. If something can run faster, use less memory, or be structured more cleanly, that is the kind of problem I want to solve.

Along the way I have contributed to several major open-source projects. I was one of the core members behind PhilZ Touch Recovery, one of the most popular custom recoveries in the Android modding scene, and one of the first developers to introduce a full touch-mode interface into ClockworkMod recovery at a time when every recovery was still navigated with volume keys. I later helped set the foundations for TWRP (Team Win Recovery Project), which became the standard custom recovery for Android devices. I have also contributed to the Linux kernel, Sabermod toolchains, and pushed upstream patches for SELinux after developing an interest in security hardening. That work involved upstreaming kernel patches, adapting drivers to newer hardware, and working through the kind of low-level debugging that teaches you how systems actually behave under pressure.

On the security side, I have taken on and closed bug bounties from Google, Broadcom, and Qualcomm, identifying and responsibly disclosing vulnerabilities in Android, wireless chipset firmware, and baseband processors. That kind of work requires reading disassembly for hours, understanding hardware trust boundaries, and knowing exactly where silicon vendors cut corners. It is the intersection of low-level systems knowledge and security research, and it is where I do my best work.

My interests span embedded systems, low-level programming, memory management, CPU scheduling, storage internals, networking, RF systems, firmware reverse engineering, and binary analysis. Breaking apart a firmware image and understanding how it works is one of the most satisfying things in this field. More recently I have been working with web technologies, network infrastructure, blockchain, and full-stack development. I have also been experimenting with Rust and building CLI tooling focused on token optimization for AI-assisted development workflows.

What this site is

debtman.dev started because my technical notes were scattered across Telegram group chats and random GitHub repositories. I originally created a repo just to explain how memory allocation works, but the messages kept piling up in different places with no structure. I had the domain sitting there unused, and after thinking about it for a long time, I decided to pull the trigger and consolidate everything into one proper blog.

The goal is simple: take a subject, overanalyze it in a way that is both thorough and genuinely understandable, and write it up so that both experienced engineers and people who are just getting started can follow along. Not in a boring textbook way. Each article is packed with detail because that is how I like to learn things myself. I pick one topic, go deep, and try to make the result something that is actually useful to read.

What you will find here

Every article on this site is a long-form technical deep dive. Thousands of words, multiple sections you can jump between, code samples, protocol breakdowns, formulas, and real-world examples. The blog covers:

  • Networking protocols - TCP, QUIC, BGP, DNS, HTTPS/TLS, and how they actually behave under the hood
  • RF and wireless - WiFi, 5G NR, BLE, LoRa, GPS, radar, software defined radio
  • Systems internals - Linux kernel scheduling, memory management, CPU architecture, storage
  • Algorithms and compression - Video codecs, search engine ranking, matching algorithms
  • Embedded and low-level - Firmware, drivers, binary analysis, hardware interfaces

The labs

Every article has a matching interactive lab. Reading about a TCP handshake is one thing. Watching SYN, SYN-ACK, and ACK packets animate across a sequence diagram while the state machine updates in real time is something else entirely. The labs let you step through concepts at your own pace, toggle between beginner and advanced explanations, and experiment with parameters to see how things change. They work on any device with keyboard navigation and full accessibility support.

The idea is that reading and doing should go together. You read the article to understand the theory, then you play with the lab to see it in action.

Why "debtman"

Technical debt is everywhere. Every system carries it. Understanding it, managing it, and sometimes just living with it is part of the job. The name felt right.

For students and learners

If you are a student, self-taught developer, or someone trying to understand how things work at a deeper level, this site is built with you in mind. Every article is written so that you do not need a textbook next to you to follow along. Technical terms are explained when they first appear, and the labs give you a hands-on way to reinforce what you read. I hope these resources help you the way I wish similar resources had helped me when I was starting out.

Get in touch

I am available for freelance work and consulting. Whether it is systems optimization, embedded development, firmware analysis, full-stack projects, or technical writing, feel free to reach out.