# Easy firmware updates over LoRa This guide shows the shortest manual path for sending firmware from a computer to a MeshCore node over LoRa. Choose the package type for the **destination** node: | Destination | Update type | Files needed to build the `.mota` | Installer | | --- | --- | --- | --- | | ESP32 | Full firmware | New non-merged application `.bin` | ESP32 A/B firmware slots | | nRF52 | In-place delta | Exact running `firmware.hex` and new `firmware.hex` | Exact-board OTAFIX bootloader | An nRF52 node cannot install an ESP32-style full-image container. It deliberately accepts only an in-place delta built against its exact running firmware. ## Temporary OTA channel used in this guide | Setting | Value | | --- | --- | | Center frequency | 909.950 MHz | | Bandwidth | 250 kHz | | Spreading factor | SF5 | | Coding rate used in this guide | CR5 | | Example window | 120 minutes | The copy/paste command is: ```text tempradio 909.950,250,5,5,120 ``` The fourth value is the transmit coding rate. This guide uses CR5, but the participating nodes' coding rates do not need to match. `tempradio` is not saved and the node returns to its normal radio settings when the window ends or the node reboots. This frequency is intended for North American configurations. Confirm that it is permitted in your location and change it when necessary. ## Before you start Both paths require: - An OTA-enabled build whose artifact filename contains `-ota-` on the destination, plus an OTA-enabled repeater on every intermediate hop. The `-ota-` stamp confirms that LoRa OTA is compiled into the build. Portable logging, portable MQTT, and untagged builds cannot perform LoRa OTA; FULL logging OTA builds can. - An OTA-enabled MeshCore source connected to the computer by USB serial, or an ESP32 WiFi companion/FULL ESP32 source connected over WiFi as described below. - Overlapping `tempradio` windows on the source, destination, and every repeater needed between them. LoRa OTA packets are generated, received, and relayed only while `tempradio` is active. If any required window closes, the transfer stops making progress and can resume during a later overlapping window. `build.sh` provides a `*_repeater_lora_ota_no_external_sensors` build for every standalone ESP32 and nRF52 repeater target. The normal repeater build keeps its external-sensor support. The `-ota-` sibling omits optional external I2C environmental sensors to preserve the update workspace, while retaining board-native features such as its display, buttons, battery monitoring, and integrated GPS. RP2040 and STM32 repeaters do not currently have a safe self-apply path and therefore cannot install LoRa firmware updates. ESP32 `*-full-ota-*` artifacts retain all compiled features and enable LoRa OTA for every FULL role, including room servers, sensors, observers, and bridges. A FULL image requires its expanded partition table: install the matching merged image over USB once before installing later non-merged FULL updates over LoRa. The `*-full-ota-*` profile uses MQTT with logging off. Use a `*-full-logging-ota-*` artifact when USB debug and packet logging are needed instead; that diagnostic profile explicitly disables MQTT and can produce substantial serial output. ### Choose the source radio Use an OTA-enabled MeshCore node as the source. It receives the update folder from the computer, then advertises it over LoRa. ESP32 USB/WiFi companions and FULL ESP32 roles include the required transport. A small set of high-capacity classic ESP32 companions keep their normal image and provide a separate `-full-ota-` image with 100 contacts, 8 group channels, and a 16-frame offline queue. Install that variant's merged image over USB once before using it. Connect the source by USB serial or, when supported, by WiFi. For USB serial, confirm that its USB CLI accepts: ```text ota folder on ``` If an older build reports that `OTA_FOLDER_SERIAL` is not compiled in, install a current `-ota-` or `-full-ota-` build first. Do **not** use a KISS modem: KISS firmware is a TNC/KISS frame interface and does not provide the MeshCore CLI or the OTA-folder transport that `motatool serve` requires. For an ESP32 WiFi companion or FULL ESP32 source with active WiFi, use its dedicated OTA seeder: ```bash motatool serve --dir ./motas --tcp :5001 -v ``` Port `5001` is separate from the companion application port (`5000`) and the infrastructure WebConfig/browser-OTA port (`80`). On a FULL repeater or room server, `start webconfig` can bring up the saved WiFi connection. Other FULL roles with browser OTA support can raise `MeshCore-OTA` with `start ota` and use `192.168.4.1:5001`. The TCP seeder auto-attaches; do not also run `ota folder on` for USB serial. ## Install `motatool` Install Rust if necessary, then install the standalone packaging and serving tool: ```bash git clone https://github.com/vk496/motatool cargo install --path ./motatool ``` ## ESP32: package a full firmware image The destination must be an OTA-capable ESP32 with an A/B partition table. Download or build the new non-merged `.bin` application for the destination's exact board **and role**. Do not use an ESP32 `-merged.bin` factory image. Put the application firmware in a working directory, then build a full `.mota` container. For example: ```bash mkdir -p ./motas motatool build --fw ./Heltec_v3_repeater-ota-v1.16.05.bin --out-dir ./motas motatool verify ./motas/*.mota ``` Replace the example filename with the firmware for the destination's exact target. With no `--base` argument, `motatool build` creates a full-image update. The firmware must contain its MeshCore `EndF` identity trailer so `motatool` and the destination can verify the target, hardware, and version. Do not continue if `motatool verify` reports a failure. ## nRF52: package an in-place delta ### 1. Install and check the OTAFIX bootloader This is a one-time prerequisite. Install the OTAFIX bootloader built for the destination's **exact board** from the [OTAFIX 2.4 nRF52 bootloader release](https://github.com/mikecarper/Adafruit_nRF52_Bootloader_OTAFIX/releases/tag/0.9.2-OTAFIX2.4). Follow the release's board-specific installation and erase instructions. If it does not contain the destination's exact board, this LoRa install path is not yet available for that board; never substitute a similar board's bootloader. Before preparing or downloading a LoRa update, run this on the destination: ```text ota self ``` Continue only if the reply includes: ```text bootloader: apply OK ``` The reply also contains the running firmware's `base_hash`. Save it for the package check below. A stock, legacy, or older OTAFIX bootloader without `.mota` in-place-apply support will report that apply support is missing, and `ota install` will refuse to reboot into it. ### 2. Keep the exact current and new application images You need the raw `.pio/build//firmware.hex` from the build that is **actually running**, plus the corresponding `firmware.hex` from the new build. Save the current file before building the new version, because PlatformIO reuses that path. For example: ```bash # Save this immediately after building/flashing the version now running on the node. cp .pio/build/Heltec_t114_repeater/firmware.hex ./Heltec_t114_repeater-running.hex # After checking out and building the new version, save its image separately. cp .pio/build/Heltec_t114_repeater/firmware.hex ./Heltec_t114_repeater-new.hex ``` Replace `Heltec_t114_repeater` with the destination's exact PlatformIO environment. The two images must be for the same board and role, and both must contain their `EndF` trailers. Do not pass a release `.uf2` or BLE-DFU `.zip` to `motatool`; those are installation containers rather than raw application images. Keeping a file with the same version label is not enough: the base must be byte-for-byte identical to the running application. The hash check in the next step proves that it is the right file. On RAK4631 repeaters, use the `RAK_4631_repeater_lora_ota_no_external_sensors` environment. It retains built-in battery monitoring but omits optional external environmental sensor packages so the delta fits the safe in-place workspace. ### 3. Build and check the in-place delta ```bash mkdir -p ./motas motatool build \ --base ./Heltec_t114_repeater-running.hex \ --fw ./Heltec_t114_repeater-new.hex \ --patch-type in-place \ --out-dir ./motas motatool verify ./motas/*.mota ``` `motatool` prints the generated filename. Inspect that file: ```bash motatool inspect ./motas/GENERATED_FILENAME.mota ``` Check all three of these before serving it: - `codec_id` is `2 (detools-in-place)`. - `base_hash` is the same 8-byte value reported by the destination's `ota self` command. - The numeric `target_id` exactly matches `target:` in the destination's `ota status`, and the hardware and firmware version identify the intended board and role. If `inspect` shows `N/A` for the human-readable target name, the tool's name table is older than that environment; the numeric IDs still must match. The default `--inplace-memory 0x98000` and 4096-byte segment size match the supported MeshCore OTAFIX builds; do not override them for this normal nRF52 flow. Do not continue if verification or any identity check fails. ## Transfer and install either package ### 1. Start the temporary OTA channel On the source node, destination node, and every intermediate repeater, run: ```text tempradio 909.950,250,5,5,120 ``` All participating nodes must use the same frequency, bandwidth, and spreading factor. Their time windows must overlap. Start with the farthest hop (the destination) and work back toward the source when using `tempradio`. If you administer the destination over LoRa, the controller used to send later `ota` commands must also be able to communicate on this temporary channel. For unattended nodes, use synchronized `tempradioat` entries instead of manually starting the windows. Ensure the nodes' clocks are set before using `tempradioat`. ### 2. Serve the update from the computer Close any serial terminal using the source node's USB port, find its device name, and start the server: ```bash motatool serve --dir ./motas --serial /dev/ttyACM0 -v ``` Replace `/dev/ttyACM0` with the USB serial device of the source companion selected above. `motatool` attaches the folder to the source, which advertises the update over LoRa while its temporary-radio window is active. KISS modem serial ports cannot be used here. Leave this command running until the destination finishes downloading. ### 3. Find and download the update On the destination node, check its state and ask for nearby updates: ```text ota status ota ls ``` Discovery is asynchronous. Wait a few seconds and run `ota ls` again if the list is initially empty. Select the entry marked `[yours]`: it should say `full` for the ESP32 path or `delta` for the nRF52 path. If it is entry 1, run: ```text ota pull 1 flash ``` Monitor the transfer: ```text ota status ``` The update is ready when the status says `ready to install`. OTA is deliberately the lowest-priority mesh traffic. At the temporary-radio settings in this guide, allow roughly **one hour** for a typical ESP32 full image over a quiet, direct link. That is a planning estimate, not an upper bound: repeaters, retries, weak links, and normal mesh traffic can extend it well past an hour. The 120-minute example window is intentional. If necessary, start another overlapping `tempradio` window; the download resumes rather than starting over. ### 4. Verify and install Once the destination reports `ready to install`, run: ```text ota install ``` The destination verifies the complete package again before approving it. ESP32 installs the full image into its inactive A/B slot. nRF52 checks the base hash and bootloader capability, then reboots into OTAFIX; the bootloader independently rechecks the package, applies the delta in place, and verifies the resulting image. Pre-install failures leave the running firmware unchanged and report the reason. If power is lost after an nRF52 in-place apply has begun, OTAFIX will not boot a partial image; it enters recovery DFU so a known-good application can be restored. After the node returns, reconnect on its normal radio channel and confirm: ```text ota status ``` ## Quick troubleshooting - **Nothing appears in `ota ls`:** confirm that `motatool serve` is still running and every required node has an active `tempradio 909.950,250,5,5,120` window. - **The CLI says LoRa OTA is not included:** that firmware does not contain the LoRa OTA feature. `tempradio` cannot enable it; install a supported `-ota-` repeater build over WiFi or USB first. - **The update is marked `[other hw]`:** it is for a different board or firmware role. Do not install it. - **An nRF52 node does not list a full update:** this is intentional. nRF52 accepts only an in-place delta. - **nRF52 reports no bootloader apply support:** install the exact-board in-place-delta OTAFIX bootloader before trying LoRa OTA. - **nRF52 reports a base mismatch:** the file passed to `--base` is not the exact application running on the destination. Rebuild the delta from the correct saved `firmware.hex`. - **The download stalls:** check the source, destination, and intermediate repeaters. Restart matching, overlapping temporary-radio windows if one expired. - **The serial port is busy:** close the serial terminal before starting `motatool serve`. - **The destination rejects the package:** verify the source files, their `EndF` trailers, the package's target/hardware identity, and the result of `motatool verify`. For additional commands and safety details, see [the full OTA user guide](ota_user_guide.md). For protocol and container internals, see [the OTA protocol specification](ota_protocol.md).