MeshCore/docs/ota_easy.md

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	125 kHz
Spreading factor	SF5
Coding rate used in this guide	CR5
Example window	120 minutes

The copy/paste command is:

tempradio 909.950,125,5,5,120

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:

• Standard, non-logging Keymind OTA firmware on the source, destination, and intermediate nodes. Logging and MQTT builds do not include LoRa OTA; use WiFi or USB to update those.
• A source node connected to the computer by USB serial.
• 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.

Install motatool

Install Rust if necessary, then install the standalone packaging and serving tool:

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:

mkdir -p ./motas
motatool build --fw ./Heltec_v3_repeater-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. 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:

ota self

Continue only if the reply includes:

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/<environment>/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:

# 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_no_external_sensors_lora_ota environment. It retains built-in battery monitoring but omits optional external environmental/GPS sensor packages so the delta fits the safe in-place workspace.

3. Build and check the in-place delta

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:

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:

tempradio 909.950,125,5,5,120

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:

motatool serve --dir ./motas --serial /dev/ttyACM0 -v

Replace /dev/ttyACM0 with the source node's serial device. motatool attaches the folder to the source, which advertises the update over LoRa while its temporary-radio window is active.

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:

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:

ota pull 1 flash

Monitor the transfer:

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:

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:

ota status

Quick troubleshooting

• Nothing appears in ota ls: confirm that motatool serve is still running and every required node has an active tempradio 909.950,125,5,5,120 window.
• 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. For protocol and container internals, see the OTA protocol specification.