ThinkNode M6 Companion (Bluetooth): node never advertises BLE on any version (v1.13.0–v1.16.0); USB bootloader healthy, hardware confirmed good on Meshtastic

[benskigomez]

Summary

The Elecrow ThinkNode M6 Companion (Bluetooth) firmware does not advertise over BLE after a clean flash. The node is never discoverable by the MeshCore app or by a raw BLE scanner (nRF Connect) on any companion version offered in the flasher (v1.13.0 through v1.16.0). The nRF52840 UF2 bootloader is healthy, and the same unit runs Meshtastic firmware without issue, so the hardware is good. The fault appears specific to the M6 Companion BLE build.

Hardware

• Device: Elecrow ThinkNode M6 (outdoor solar node, screenless)
• MCU: nRF52840
• Radio: SX1262
• Stock firmware: Meshtastic — confirmed working, node active on the mesh

Firmware

• Source: flasher.meshcore.io, official "Elecrow ThinkNode M6" target
• Role: Companion Bluetooth ("Radio can only connect via Bluetooth")
• Versions tested (Erase Flash + Flash each time): v1.16.0, v1.15.0, v1.14.1, v1.14.0, v1.13.0
• Result: identical on every version — no BLE advertising

Expected behavior

After flashing Companion Bluetooth firmware, the node advertises over BLE, is discoverable by the MeshCore app / a BLE scanner, and pairs with PIN 123456 (screenless device).

Actual behavior

The node never advertises. It does not appear in the MeshCore iOS app, and it does not appear in a raw, unfiltered nRF Connect scan. The device behaves as though BLE is off entirely.

Steps to reproduce

1. In flasher.meshcore.io, select the ThinkNode M6 target and Companion Bluetooth role.
2. Erase Flash, then Flash (any version 1.13.0–1.16.0).
3. Boot the node.
4. Scan with the MeshCore app → nothing.
5. Scan with nRF Connect (raw BLE) → nothing.

Diagnostics performed

• Raw BLE scan (nRF Connect): no advertisement from the M6 on any firmware version. This rules out app-side filtering, iOS BLE caching, stale pairing keys, and "forget device" issues — there is nothing being advertised at all.
• UF2 bootloader: healthy. Double-tap reset mounts the drive, which correctly self-identifies as ThinkNodeM6. Both drag-and-drop UF2 and web-flasher methods complete successfully.
• Reset behavior: a single reset re-enumerates USB, so the chip responds to the reset line.
• USB serial (115200, COM4): blank console. Expected for a BLE-only Companion build (no text console), so not diagnostic on its own — noted for completeness.
• Clean state: Erase Flash performed before every flash; behavior is identical across all versions.

Hardware confirmed good

The same physical unit runs Meshtastic firmware correctly and is active on the LoRa mesh, confirming the nRF52840, SX1262, and antennas are healthy. The fault is isolated to the MeshCore M6 Companion BLE firmware.

Possibly related

• XIAO nRF52840 + Wio-SX1262: MeshCore stops working after power cycle, no BLE advertising and no response over USB #2068 — XIAO nRF52840 + SX1262: BLE stops advertising, no USB response, works again under Meshtastic (same MCU + radio combo, same "no BLE advertising / hardware good on Meshtastic" signature).
• No Bluetooth code on first startup #1529 — Heltec V4: no Bluetooth code on first startup, nothing shown in app.
• There is no firmware compiled for the Elecrow ThinkNode M6 #1555 — original report that M6 firmware was missing from releases/flasher.

Environment

• Phone: iPhone 15, iOS 26.5
• MeshCore app: iOS, app version 1.45.0
• Flashing host: Windows, Chrome

Notes

M6 Companion BLE support was added in v1.12.0. Happy to run additional diagnostics, capture serial output from a different build, or test a debug image to help isolate whether BLE init is failing or radio init is halting boot before BLE comes up.