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This document describes the over-the-air (OTA) update system used by the Research And Desire wireless Remote (RADR), including the update chain, state machine flow, and what components get updated.

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Overview

RADR uses a two-part OTA update system:
ComponentDescriptionBinary
FirmwareESP32 application binaryfirmware.bin
FilesystemLittleFS partition containing device registry and protocol specslittlefs.bin
The filesystem update is particularly important for device support — it contains the Buttplug.io registry that maps Bluetooth service UUIDs to device configurations. This allows adding support for new devices without requiring firmware changes.

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Update Architecture

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Update Server

Updates are served from Supabase Storage. The server URL is defined in platformio.ini: 
UPDATE_SERVER_URL="https://acjajruwevyyatztbkdf.supabase.co/storage/v1/object/public/radr-firmware"
Binary URLs follow the pattern:
  • Firmware: {UPDATE_SERVER_URL}/master/firmware.bin
  • Filesystem: {UPDATE_SERVER_URL}/master/littlefs.bin

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State Machine Flow

Updates are managed by the RADR state machine. The update flow is triggered from the Settings menu.

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State Transitions

FromToCondition
settings_menuupdateUser selects “Update Device” + WiFi connected
settings_menuupdate.wifiUser selects “Update Device” + WiFi not connected
update.wifiupdateWiFi connection established
updateupdate.filesystemhasFilesystemUpdate guard returns true
updateupdate.softwarehasSoftwareUpdate guard returns true (no filesystem update)
updateupdate.doneNo updates available
update.filesystemupdate.softwareFilesystem update complete + software update available
update.filesystemrestartFilesystem update complete, no software update
update.softwarerestartSoftware update complete (always restarts)
update.donerestartUser acknowledges

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What Gets Updated

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Firmware Update

The firmware update replaces the ESP32 application binary. This includes:
  • Core application logic
  • UI and display code
  • Bluetooth stack and device communication
  • State machine and navigation
  • Input handling (encoders, buttons, bumpers)
Implementation: updateSoftwareTask() in src/tasks/update.cpp 
void updateSoftwareTask(void *pvParameters) {
    // Uses ESP32 HTTPUpdate library
    httpUpdate.setRebootOnUpdate(true);  // Auto-reboot on success
    
    String url = String(UPDATE_SERVER_URL) + "/master/firmware.bin";
    httpUpdate.update(client, url);
}
The firmware update automatically reboots the device on success.

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Filesystem Update

The filesystem update replaces the LittleFS partition, which contains:
FilePurpose
/registry.jsonMaps BLE service UUIDs to protocol spec files
/protocols/*.jsonButtplug.io v4 device configuration files
Implementation: updateFilesystemTask() in src/tasks/update.cpp 
void updateFilesystemTask(void *pvParameters) {
    LittleFS.end();  // Unmount before update
    
    httpUpdate.setRebootOnUpdate(false);  // Don't reboot yet
    
    String url = String(UPDATE_SERVER_URL) + "/master/littlefs.bin";
    httpUpdate.updateSpiffs(client, url);
    
    LittleFS.begin();  // Remount after update
}
The filesystem update does not trigger an automatic reboot. This allows both filesystem and firmware to be updated in sequence before restarting.

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Registry Update Chain

When the filesystem is updated, the Buttplug.io device registry is refreshed: The registry is loaded at boot time by initRegistry() in src/devices/registry.cpp:
  1. Hardcoded devices are registered first (e.g., OSSM)
  2. /registry.json is read from LittleFS
  3. Each service UUID is mapped to a ButtplugIODeviceFactory
  4. Protocol specs are loaded on-demand when devices are discovered

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Update Availability

Update availability is determined by guard functions in src/state/guards.hpp: 
bool hasFilesystemUpdate(const State &state, const Event &event) {
    return isFilesystemUpdateAvailable;
}

bool hasSoftwareUpdate(const State &state, const Event &event) {
    return isSoftwareUpdateAvailable;
}
These flags are controlled by:
FlagSet When
isSoftwareUpdateAvailableFORCE_UPDATE compile flag, or server indicates update
isFilesystemUpdateAvailableFORCE_UPDATE compile flag, or server indicates update
The current implementation has a TODO for automatic update checking. Currently, updates are triggered manually and availability must be set via compile flags or external mechanisms.

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Key Source Files

FilePurpose
src/tasks/update.cppUpdate task implementations (updateSoftwareTask, updateFilesystemTask)
src/tasks/update.hUpdate task declarations and availability flags
src/state/machine.hState machine definition with update states
src/state/guards.hppGuard functions for update availability
src/devices/registry.cppRegistry initialization from LittleFS
data/registry.jsonService UUID to protocol spec mappings
data/protocols/*.jsonButtplug.io v4 device specifications

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Development Notes

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Forcing Updates

For development and testing, use the FORCE_UPDATE compile flag: 
build_flags =
    -D FORCE_UPDATE
This sets both isSoftwareUpdateAvailable and isFilesystemUpdateAvailable to true.

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Local Filesystem Updates

When developing locally, use PlatformIO’s “Upload Filesystem” feature: 
pio run --target uploadfs
This uploads the contents of the data/ directory to the LittleFS partition.
“Upload Filesystem” erases the existing LittleFS partition before writing. Any runtime modifications will be lost.

Device Registry

How RADR discovers and creates device instances from BLE service UUIDs.

Web Flasher

Manual firmware flashing via browser.