John Paul Chacha

Blog

Writing on technology, software, electronics, and life in Kenya.

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2025 2 articles

Power Control Unit - 2022 Upgrade for UpX4 Neo 2020

UpX4 Neo 2020
John Paul Chacha · Thu, 17th Apr 2025 · 1,608 reads

Efficiency improvement for the UPX-4 by supply voltage adaptation

Malware Masquerading as Chasys Draw IES Viewer

Press Releases
John Paul Chacha · Wed, 5th Nov 2025 · 18 reads

Advisory on a new piece of malware that masquerades as an older version of Chasys Draw IES Viewer
2021 1 article

Building the UpX4 Neo 2020

UpX4 Neo 2020
John Paul Chacha · Mon, 23rd Aug 2021 · 6,569 reads

A detailed build log of a handbuilt 3-channel amplifier — custom autotransformer, modular outputs, homebrew Bluetooth, built during the COVID-19 lockdowns in Kenya
2019 2 articles

Corel Photo-Paint's CPT File Format

Computer Graphics
John Paul Chacha · Sun, 10th Feb 2019 · 7,713 reads

A deep dive into the binary structure of Corel Photo-Paint's native file format — reverse engineered from scratch

Visual Studio and x64 Inline Assembly

Computer Software
John Paul Chacha · Fri, 27th Dec 2019 · 5,623 reads

Getting inline assembly to work in 64-bit Visual Studio — what changed, what broke, and how to work around it
2018 5 articles

Part 1: The road to the UpX-4 (2011)

UpX4 DreamPump
John Paul Chacha · Wed, 5th Sep 2018 · 12,918 reads

How the original UpX-4 amplifier came to be — the design decisions, the build, and the lessons learned

Part 2: Face-lift and Bluetooth (2018)

UpX4 DreamPump
John Paul Chacha · Wed, 5th Sep 2018 · 9,335 reads

Revisiting the original UpX-4 amplifier from 2011 with a cosmetic overhaul and a new Bluetooth audio module

The Buruburu That Was

Life in Kenya
John Paul Chacha · Wed, 5th Sep 2018 · 10,270 reads

Reflections on a Nairobi neighbourhood and how it has changed beyond recognition over the years

Of Great Expectations

Life in Kenya
John Paul Chacha · Wed, 5th Sep 2018 · 5,910 reads

A personal reflection on ambition, circumstance, and making things in Kenya

Theft by Compute

Computer Software
John Paul Chacha · Sat, 15th Dec 2018 · 14,251 reads

Malware creators have found a new way of making money off you — by turning your machine into a crypto-currency mining node in a distributed computing network, at your expense
2017 2 articles

The MHz Myth

Computer Hardware
John Paul Chacha · Sat, 2nd Dec 2017 · 7,852 reads

Between a 2 GHz phone and a 1 GHz desktop, which is faster? If you said the phone, you're wrong — and here's a deep dive into why

History of Lena

Computer Graphics
John Paul Chacha · Sat, 2nd Dec 2017 · 9,904 reads

The story behind the most widely used test image in computer history — and where it unexpectedly came from