HaloKeymind/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
MeshTower V2 SD target	Full firmware or in-place delta	New firmware.hex; a delta also needs the exact running firmware.hex	Matching SD-aware OTAFIX bootloader

A normal nRF52 target cannot install a full-image container. It deliberately accepts only an in-place delta built against its exact running firmware. The MeshTower V2 microSD target is the exception because it stages the complete container off-chip; see MeshTower V2 microSD LoRa OTA.

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:

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. The -ota- stamp confirms that the node can discover, download, verify, and install LoRa OTA. Intermediate repeaters do not need an OTA-enabled build: current repeater firmware relays OTA packets opaquely without storing or installing them. Portable logging, portable MQTT, and untagged builds cannot install 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, consumed, and relayed only while tempradio is active. Intermediate repeaters apply their normal forwarding filters, duplicate checks, and flood limits; they do not interpret the OTA payload. 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 and can serve as an intermediate OTA relay, but it cannot download or install an update for itself. 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. ESP32 -ota- siblings also retain the compact browser WiFi uploader (start ota) and use a 254-entry neighbor table. RP2040 and STM32 repeaters do not currently have a safe self-apply path, but current repeater firmware can still relay OTA packets opaquely during TempRadio.

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:

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:

motatool serve --dir ./motas --tcp <source-host>: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:

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-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. 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_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

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 909.950,250,5,5,120

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:

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:

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 909.950,250,5,5,120 window.
• The CLI says LoRa OTA is not included: that firmware does not contain the LoRa OTA feature. If it is the source or destination, install a supported -ota- build over WiFi or USB first. An intermediate repeater does not need the OTA CLI and can relay opaquely while its matching tempradio window is active.
• 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 for internal-flash targets. The MeshTower V2 microSD target accepts full images with its matching SD-aware bootloader.
• 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.