Why nRF24 Scanner Apps Black-Screen on Dual-Chip PINGEQUA 2-in-1 Flipper Boards — and How We Fixed It

Why nRF24 Scanner Apps Black-Screen on Dual-Chip PINGEQUA 2-in-1 Flipper Boards — and How We Fixed It

PINGEQUA 2-in-1 nRF24 + CC1101 board with dual antennas on Flipper Zero, Channel Scanner running

If you've run a generic nRF24 channel scanner on a 2-in-1 (nRF24 + CC1101) Flipper Zero board, you may have watched the screen go black in the middle of a scan. Here's why it happens — and what we did about it.

The symptom

On a dual-chip board, launching a third-party nRF24 channel scanner and starting a signal scan can blank the Flipper display partway through.

Flipper screen filling with black from the bottom during an nRF24 scan on a dual-chip board
A third-party nRF24 channel scanner on a 2-in-1 board — the display fills black from the bottom mid-scan.

This isn't unique to our hardware. The most-forked community nRF24 app carries an open report describing the same class of failure:

"the screen sometimes completely blanks for 5 seconds or so during scanning. If the scan time is lowered the blanking is observed more often."
— flipperzero-nrf24 issue #15, open since 2022

Why it hits dual-chip boards harder

A 2-in-1 board wires the nRF24 and CC1101 in parallel on one SPI bus, software-selected by each chip's dedicated CSN line. A scanner written for a single nRF24 only drives its own CSN — it never deselects the second chip. Both chips can then respond on the shared bus at once, and a scanner that holds the SPI bus continuously can starve the display-refresh task. The result you see is a blank screen.

We're not the only ones to flag the legacy-app gap — even our own product notes warn that legacy applications may have hardcoded pin definitions and recommend apps with proper GPIO/SPI handling.

ℹ️ This root-cause description is our engineering analysis of the observed behavior, not a vendor-confirmed defect.

Why we rewrote instead of patched

Patching a single fork's quirks doesn't fix the underlying bus-arbitration problem, and it doesn't survive the next firmware update. So in early 2026 we rebuilt the toolkit against the official Furi SDK — no fork-private symbols, one clean SPI arbiter.

What changed

  • Single-handle SPI arbiter — every transaction goes through one bus handle (furi_hal_spi_bus_handle_external), the one every firmware ships.
  • Idle chip is always deselected — before any access, the other chip's CSN is driven high. The bus is never left ambiguous, so the display never starves.
  • One .fap, every firmware — runs on Official Flipper firmware (OFW), Momentum, Unleashed, RogueMaster, and Xtreme. No recompiling.
PINGEQUA RF Lab Channel Scanner running cleanly — live 2.4 GHz spectrum, no black screen
The same hardware running RF Lab — full 126-channel spectrum, no display starvation.

What v0.5.2 adds

Beyond the rewrite: human-readable export filenames (scan_2026-05-15_143022_ch42.csv) and an on-device About screen with scannable QR codes for the shop and source repo.

RF Lab About screen with a scannable QR code to the shop
The on-device About screen — scan the QR to open the shop or the source repo.

See it in action

RF Lab main menu navigation on Flipper Zero
Main menu — Scanner, Jammer, About
RF Lab main menu on a Flipper Zero with the 2-in-1 board
On the hardware
RF Lab NRF24 jammer in WiFi pilot-aware OFDM mode at +20 dBm
7-mode NRF24 jammer

Try it on your setup

  1. Download pingequa_rf_toolkit.fap from GitHub Releases
  2. Drag it into /ext/apps/GPIO/ in qFlipper
  3. Launch from Apps → GPIO → PINGEQUA RF Lab

No GPIO remapping, no per-firmware setup.

What's next is up to you

The v0.6 roadmap is open. Want a Sub-GHz spectrum view, dual-band sweep, or custom scan presets? Open an issue — the next release is built on what people actually ask for.

Open box. Open source.

nRF24L01+PA & CC1101 on a single SPI bus — for Flipper Zero.

📦 Download the FAP (free) 🛒 Get the hardware

Sources & further reading: flipperzero-nrf24 #15 · Flipper Furi SDK docs · GEO: Generative Engine Optimization (arXiv:2311.09735)

PINGEQUA RF Lab is an open-source FAP (MIT) for Flipper Zero, built for the PINGEQUA 2-in-1 RF Devboard (nRF24L01+ + CC1101). Source: github.com/pingequalab/rf-lab

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