Field report: a user on the stock SF8 "EU/UK (Narrow)" preset saw reception
drop from ~1-5 msg/min to ~1/3h with Pwr save on, unaffected by a better
antenna. Root cause, confirmed against the SX1262 datasheet and RadioLib's
own maintainers (jgromes/RadioLib#1597, closed as inherent chip behaviour):
the SX126x's duty-cycle preamble detection needs the sender's actual
preamble to closely match what we've configured our receiver to expect.
A mismatch — e.g. a repeater still on pre-v1.16 firmware sending 16 symbols
against our 32 — doesn't cost a little sensitivity, it silently drops every
packet from that sender regardless of signal strength. There's no local
parameter fix: shortening minSymbols to tolerate shorter preambles directly
shortens the wake-window's correlator dwell time, trading the preamble
mismatch failure mode for a marginal-signal one instead. Checked whether
IoTThinks' MeshCore fork solved this differently — it doesn't hit the
problem at all, because its "power saving" only light-sleeps the MCU on the
radio's own GPIO interrupt and never touches RX duty-cycle.
examples/companion_radio/MyMesh.h now defines FEAT_RX_POWERSAVE 0, gating
out the Settings row, the Diagnostics RXPS watchdog row, and every call site
that would apply rx_powersave to the radio or CAD auto-enable — including
forcing setPowerSaving(false) unconditionally so a stale rx_powersave=1 byte
from before this change can't do anything either. The real duty-cycle
implementation in RadioLibWrapper/CustomSX1262Wrapper is left in place,
unneutered, for if a network-wide compatibility mechanism (e.g. the
still-unused ADV_FEAT1/FEAT2 advert bits) is ever built to make it safe.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
README had drifted from the firmware in several places:
- Supported Devices listed only the three nRF52 boards; Heltec V3/V4 were
missing entirely, as was any mention that ESP32-S3 flashes differently.
Flashing is now split per MCU, with the merged-vs-app-only .bin trap
spelled out — that one costs an afternoon to diagnose from a dark screen.
- It advertised a Lemon/Default font switch that was retired in v1.23; there
is one unified misc-fixed 6x9 font now and no font setting at all.
- tools/README claimed ENABLE_SCREENSHOT had to be added by hand, directly
contradicting README's "no special build flags required". The envs have
carried the flag for a while; rewrote the file to cover all four tools.
- "S key for screenshot" described screenshot.py's menu, not the device —
screenshots are driven entirely from the host via CMD_GET_SCREENSHOT.
Structurally, general notes (factory reset on migration, BLE-over-USB
priority) sat at the tail of the ESP32 subsection and read as ESP32-specific;
they're now placed where they apply. Heltec wiring moved out of Supported
Devices into its own section so the device table stays scannable, and the
Solo Tools heading is no longer a link (it was generating a garbage anchor).
New docs/solo_features/external_keyboard.md covers CardKB and the wired
joystick: shortcut table, Full vs Compact, and the pin assignment. The pins
are marked as verified on real V4 hardware only — V3 inherits them from
Heltec's documented pin-compatibility and hasn't been checked on a board.
FEATURES.md (roadmap + code audit, developer-only) moves to
docs/development/roadmap.md; nothing referenced it by path.
Adds Building from source / Releasing / Repository layout, since the release
flow was only discoverable by reading the workflow.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
JakubandClaude Sonnet 5