Sources & further reading
This site's content was compiled from a deep search of the references below, then rewritten into two levels and baked into the app. Go to the primary sources to verify details, get the newest firmware, and dive deeper.
- portapack-mayhem/mayhem-firmware (GitHub)
Canonical open-source Mayhem firmware for HackRF + PortaPack H1/H2/H4/H4M; source, releases, and wiki.
https://github.com/portapack-mayhem/mayhem-firmware
- Mayhem Firmware Wiki
Per-app documentation for the receive, transmit, and utility apps.
https://github.com/portapack-mayhem/mayhem-firmware/wiki
- Fresh Mayhem — Firmware Guide
Beginner-friendly guide to the Mayhem firmware for the PortaPack H4M + HackRF One.
https://freshmayhem.com/
- Mobile Hacker — HackRF PortaPack H4M with Mayhem Firmware
Overview of the H4M toolkit and a walkthrough of key RX/TX apps.
https://www.mobile-hacker.com/2025/05/19/hackrf-portapack-h4m-with-mayhem-firmware-a-powerful-handheld-sdr-toolkit/
- RTL-SDR — Mayhem V2 firmware overview
Look at the newer Mayhem v2 firmware features and UI.
https://www.rtl-sdr.com/tech-minds-taking-a-look-at-the-new-hackrf-portapack-mayhem-version-2-firmware/
- Lab401 — PortaPack H4M + HackRF
Vendor spec page: RX/TX app counts, hardware features, and specifications.
https://lab401.com/products/portapack-h4m
- Great Scott Gadgets — HackRF One
Official HackRF One hardware documentation (frequency range, sample rate, half-duplex).
https://greatscottgadgets.com/hackrf/one/
Disclaimer
This website is just for learning how radios work. Some apps can 'talk' on radio channels — only ever use those on channels you're allowed to, with a grown-up who knows the rules. Never do anything that could bother real airplanes, boats, phones, or emergency services.