Three photos from disassembly session:
- PCB overview with back cover removed
- PCB closeup showing component labels
- Battery connector detail
Factory firmware reflashed to verify hardware integrity. I2C bus and
display confirmed working under LilyGo firmware. RNode firmware I2C
init needs debugging — Wire.begin succeeds but no slaves respond.
Key finding: deep sleep GPIO OPEN_DRAIN configuration persists in the
battery-backed RTC domain, corrupting the I2C bus across reboots.
Wire.begin() returns false after deep sleep has been entered once.
I2C bus recovery attempt added (SCL clock-out + STOP condition) but
Wire (I2C0) peripheral remains stuck. Wire1 (I2C1) works on same pins
but no slave devices respond — bus lines may be held by stuck slaves.
Found from schematic: XL9555 DOES control VC_EN (display VCI power).
Display QSPI pins confirmed correct from schematic (sheet 4).
BHI260AP SensorLib removed (was causing boot failure due to firmware blob size).
Beacon wake cycle still disabled pending I2C fix.
Critical TODO: fix deep sleep to not set I2C pins to OPEN_DRAIN,
or add robust I2C bus recovery in early boot before PMU init.
Added SensorLib dependency (v0.3.1) with BHI260AP GPIO firmware
for controlling display power gate, haptic driver, and touch reset
via the sensor's auxiliary GPIO pins.
Fixed beacon wake cycle triggering on cold boot — disabled pending
proper deep sleep vs cold boot discrimination.
Display status: BHI260AP begin() returns false (firmware upload
failing). CO5300 QSPI driver still cannot reach display controller.
Both issues under investigation.
Standalone GPS beacon mode: when no KISS host is connected for 15s,
the RNode transmits position and battery telemetry over LoRa.
Two beacon paths:
- LXMF (recommended): encrypted per-packet messages with announces,
compatible with Sideband and any LXMF application. Supports IFAC
network authentication.
- Legacy JSON: plaintext or encrypted raw packets for simple collectors.
Key changes:
- GPS support for T-Beam Supreme S3 (L76K) and Heltec V4 (external)
- SX1262 radio fixes: IQ polarity, DCD preamble lockup, RX reliability
- LXMF identity management with NVS-backed Ed25519/X25519 keys
- IFAC authentication (CMD_IFAC_KEY 0x89) for private networks
- Per-channel serial isolation (USB, BLE, WiFi)
- GPS status page in OLED display rotation
- Provisioning via rnlog: provision-lxmf, provision-ifac
- Documentation in Documentation/BEACON.md
Fix for critical Issue: GPIO 36 on the ESP32 is an input-only pin (part of the ADC1 group along with GPIO 34, 35, and 39). This is a hardware limitation of the ESP32 microcontroller. These pins cannot be configured as outputs.
This means the current pin assignment in the firmware will not work correctly for the reset functionality, as pinMode(_reset, OUTPUT) and digitalWrite(_reset, LOW/HIGH) calls will fail to actually drive the pin. The reset pin for a generic ESP32 board should be reassigned to a GPIO that supports output mode (any GPIO that is not 34, 35, 36, or 39).
This appears to be a configuration error in the board definition that would prevent proper initialization of the SX1278 LoRa module on these board configurations.
Work in progress
Status: Boots, display works on Xiao espansion base,
radio is recognized
Todo:
PMU
Firmware hash fails even if generated and then written
Radio testing
Buttons / LEDs
other?
