Mayhem

Mayhem is the community-maintained firmware for the PortaPack, the touchscreen-and-controls add-on board that turns a HackRF One software-defined radio into a self-contained, portable transceiver. Where a bare HackRF One needs a computer running GNU Radio or SDR software to do anything, a HackRF with a PortaPack running Mayhem is a standalone handheld: it receives, transmits, records, replays and decodes across a wide frequency range using only its own screen and jog-wheel. The firmware is developed in the open by a large group of contributors under the portapack-mayhem organization on GitHub.

This deep dive documents Mayhem at reference level: what it is and where it came from (this volume), its capabilities and the important fact that transmitting is legally regulated (Volume 2), how it is installed and updated (Volume 3), and how its SD card is laid out (Volume 4). The bench unit documented here — an HackRF One with a PortaPack, referred to in the owner’s notes as the porta unit — runs Mayhem.

1.1 What it is

The hardware underneath Mayhem is two boards. The HackRF One, from Great Scott Gadgets, is a half-duplex software-defined radio that covers roughly 1 MHz to 6 GHz with up to 20 million samples per second of bandwidth; its RF chain is an RFFC5072 mixer and a MAX2837 transceiver feeding a MAX5864 baseband converter, glued to an NXP LPC4320 microcontroller through a small CPLD. The PortaPack clips onto the HackRF’s expansion headers and adds a colour touchscreen, a jog-wheel and buttons, a real-time clock, and a microSD slot. Mayhem is the firmware that runs on the LPC4320 to drive all of that as an integrated instrument.

Because the HackRF is half-duplex, it either receives or transmits at a given instant, not both — a fact that shapes several of the apps in Volume 2. It is also a wideband, uncertified radio: it can be tuned almost anywhere in its range, but where it may lawfully transmit is a separate and much narrower question, addressed in Volume 2.

1.2 The Havoc → Mayhem lineage

Mayhem’s own README states the lineage plainly: it is a fork of the Havoc firmware, which was itself a fork of the original PortaPack firmware written by Jared Boone (sharebrained) as the add-on’s stock software.

• PortaPack (sharebrained) — the original firmware, focused on a clean, stable receiver and a well-engineered UI framework.
• Havoc (furrtek) — a fork that added a large number of transmit-capable and experimental applications, giving the firmware its offensive-tooling reputation.
• Mayhem (portapack-mayhem organization) — the continuation that merged the Havoc feature set back onto an actively maintained base and has carried development since. It is a community project with many contributors; the release and build infrastructure is maintained under the organization (the work is associated with the maintainer known as eried, whose Docker images and workflows drive the builds).

The practical result is that Mayhem is where new PortaPack apps land today; the sharebrained and Havoc repositories are of historical interest, and the Mayhem tree supersedes both for a current install.

1.3 Supported hardware

Mayhem targets the HackRF One paired with a PortaPack in its several revisions — H1, H2, H2+/H2M, H4 and the newer H4M (and clones of these). The touchscreen generation and a few hardware details differ between revisions, and the project’s wiki carries a “which one to buy” page and an H1-versus-H2 comparison for anyone choosing hardware. For the purposes of this dive the firmware behaves as one product across the supported PortaPack revisions; where a feature needs a specific revision, the app itself says so.

1.4 Runs on

The devices this firmware runs on — the Firmware ↔ Device “runs on” matrix (each links to its Hack Tools deep dive):

• HackRF One (+ PortaPack) — the canonical Mayhem target; the bench porta unit runs Mayhem today.
• OpenSourceSDRLab PortaRF — an integrated HackRF-class handheld that ships pre-flashed with Mayhem.

1.5 How this dive is organized

• Volume 1 (this volume) — what Mayhem is, its lineage, and the hardware it runs on.
• Volume 2 — the capability set: receive, transmit, capture and replay, decoders and utilities — and the regulatory limits on transmitting.
• Volume 3 — installation: prebuilt nightlies versus building from source, and the firmware update flow.
• Volume 4 — the SD card: its layout, the file formats, and data management.

1.6 Version and date note

This dive was written on 2026-09-16. Mayhem’s development is delivered as dated nightly releases — the latest at the time of writing was tagged nightly-tag-2026-09-16 — with formal tagged stable releases produced much less often; the last tagged stable was v2.0.1 (April 2024). The capability catalogue in Volume 2 reflects the application set documented on the project wiki as of September 2026, which matches the contemporaneous nightlies rather than the older stable tag. Apps are added and renamed frequently, so any single app list is a snapshot.

1.7 Related elsewhere

• Hack Tools → HackRF One, PortaRF (the Firmware ↔ Device “runs on” matrix).