ZephCore v1.16.5-zephyr

The headline of this release:
Adaptive CAD, a self-tuning listen-before-talk that calibrates itself to each site;
V-Contact, an in-app admin "channel" for companions; and a batch of LoRa-driver reliability fixes.

Highlights

Fixed: ESP32 WiFi-OTA silently reverted — upload hit 100%, then booted the old firmware

On ESP32-S3 / ESP32-C boards, the app and MCUboot bootloader were using different flash partition tables,
so each OTA update landed at an address the bootloader never checked. Every upload "succeeded" and then
quietly did nothing. Both images now share one partition map, and OTA works correctly. (The XIAO C3/C6 and
T-Lora C6 used the stock layout and were never affected.)

ESP32 app slot moved to 0x10000

The ESP32 app slot moved from 0x20000 to 0x10000 — matching the Arduino / ESP-IDF offset. This is the
change that fixes OTA above, and it also enables the configurator's fast app-only update (rewrites just
the app, keeps your settings). Requires the one-time serial reflash (see Before you upgrade).

New: Adaptive CAD — listen-before-talk that tunes itself to your site

Every transmission is preceded by a Channel Activity Detection (CAD) check that listens for other LoRa
traffic and holds off if the channel is busy. How sensitive that check is has always been a single
hardcoded number — but the right value depends on where the node lives. A quiet valley node and a
50-network hilltop need very different thresholds: too sensitive and the node keeps deferring for phantom
traffic (wasted airtime, latency); not sensitive enough and it transmits over real packets (collisions).

Nodes now measure their own RF environment and adjust automatically. In the background, between
transmissions, the radio runs short calibration probes, tracks how often each sensitivity level produces a
false "busy", and settles on the lowest false-positive threshold for that site — responding to a
changing environment within an hour or two. It runs on repeaters and companions, and it is on by
default; there is nothing to configure.

• get cad — watch what it's doing: the current threshold and per-level false-positive statistics.
• set cad.auto off — turn off the auto-adjust to observe or hand-tune with set cad.offset.

Quiet sites end up more sensitive than the old fixed default (fewer stomped packets); noisy sites back
off until the false alarms stop. CAD also now uses 4 detection symbols everywhere, which improves detection
of an in-progress packet's payload (not just its preamble). Full guide, including the honest limitation
that the "missed detection" side isn't locally observable, is in
ADAPTIVE_CAD.md.
(SX127x boards have no hardware CAD and keep their RSSI-based gate.)

New: V-Contact — admin your companion from the chat app, no cable

Companions now expose a special contact named v<your-node-name>. Chat with it and your messages run the
same text CLI you'd use over USB serial — the reply comes back as ordinary chat messages. It's the easiest
way to check or change settings on a companion in the field without plugging in.

It's also used for two unsolicited notices: a restart-reason message after a reboot (so an unexpected
brownout or watchdog reset is visible instead of silent) and a one-shot low-battery alert. The whole
thing is local to your device — the v-contact has no real keypair and never creates a packet or touches
the radio, so none of this costs airtime. On by default; toggle the v_contact_enabled variable from the
app to disable.

LoRa driver reliability (LR1110 / LR2021)

• Fixed: LR1110 accepted CRC-failed packets. On the LR11xx/LR20xx family a CRC-failed receive raises
  RX_DONE and CRC_ERROR together; the driver was acting on RX_DONE alone and passing corrupt frames
  up the stack. It now gates on the error bits (matching the SX126x path).
• Ported the SX126x preamble-grace / RX-busy handling to LR11xx/LR20xx. A foreign or noise-triggered
  preamble detection could pin the channel-busy state and stall listen-before-talk recovery. The same
  SF-aware grace window and header-valid latch the SX126x driver uses now guard the LR path, so a real
  packet promotes to "receiving" and a false preamble releases after a bounded window.

Other fixes and improvements

• Classic ESP32 companion builds (TTGO LoRa32, T-Beam) now build and link correctly. The Espressif BT
  HCI controller node wasn't wired on TTGO LoRa32 (companion needs BLE), and the CLI backing the V-Contact
  chat wasn't compiled on plain (non-logging) companion builds — both fixed. Contact-table sizes on these
  DRAM-tight classic-ESP32 boards were trimmed to fit alongside the BLE controller.
• SenseCAP Solar LED devicetree fix.
• LilyGo T-Impulse Plus display fixes (follow-up to the initial port).
• Repeater + observer hybrid role wiring fixups (MQTT publisher / uplink credentials / observer mesh).
• get/set command keywords are now case-insensitive (e.g. Get cad works). Command values —
  passwords, node names, keys — remain case-sensitive as they must be.
• Platform: Zephyr west manifest advanced (continuing along the v4.4-branch).
• New -update build artifacts for OTA / manual app-only updates, published alongside the full images.
• Docs: new ADAPTIVE_CAD.md; Repeater_CLI_commands.md, ARCHITECTURE.md, and PROVIDER_CATALOG.md
  updated for the above.

Recommended upgrade checklist

1. ESP32-S3 / ESP32-C boards: flash -merged.bin once over USB/serial. WiFi-OTA can't cross this update; data survives.
2. Everything else, from v1.16.2 / v1.16.3 / v1.16.4: just flash — bonds and data survive.
3. From v1.16.1 or older: just flash — self-migrates on first boot; re-bond once.
4. From Official MeshCore: just flash — auto-formats on first boot.
5. Anything odd? Format first.