Firmware updates

The dongle's firmware ships in two halves: the P4 application image (binary, flashed into one of two 7 MB OTA partitions) and the SD-card assets (web apps + BMW data files, dropped onto the SD via USB-MSC or the admin UI).

OTA — application image

Dual-partition layout: at any time one partition holds the running firmware, the other is standby. An OTA push writes to the standby slot, verifies it, then switches the next-boot pointer. If the new image fails to boot cleanly, the bootloader rolls back to the previously-running slot automatically.

Pushing an OTA build

The dongle's /admin/ page has an OTA upload form. Drop a built bimmerz_box.bin file, wait for the upload to finish (a few seconds over the AP), the dongle reboots into the new image.

For development you can also flash directly over USB-JTAG with the ESP-IDF toolchain:

cd firmware
idf.py -p /dev/cu.usbmodem... flash

That bypasses OTA entirely and writes to flash directly. Useful when the running image won't boot.

SD-card assets — USB-MSC

Plug the dongle into a computer via USB. It exposes its SD card as a USB Mass Storage device — a removable drive in your file manager.

What you upload here:

• /web/<app>/ — the SPAs themselves. Each web app's dist/ output drops into its own folder. The dashboard probes the folder list at boot — apps appear as enabled tiles on the hub once their folder exists.
• /data/ — every BMW data file the installed apps need. Each app expects a particular layout under this root: EDIABASX reads .prg / .grp SGBDs from /data/ediabas/ecu/, NCSX reads NCS-Expert profile + manifest files from /data/ncs/, INPAX runs .ipo scripts from /data/inpa/, and newer tools document their paths in their own repos. The dongle doesn't care what's there — it just serves the namespace read-only at http://172.16.7.1/data/.

Eject the drive cleanly before unplugging. The dongle remounts FAT on the next reboot.

USB-MSC vs admin upload

USB-MSC is the fast path for bulk loads — the whole DATEN disk takes maybe 30 seconds. The admin upload is the right tool when you're already on Wi-Fi, don't have a USB cable handy, and just need to swap one file.

Reverting

The bootloader keeps the previous OTA slot intact. If a new firmware boots cleanly the rollback marker is cleared; if it crashes on boot or fails its health check, the next reboot lands on the previous slot automatically.

To force a rollback without waiting for a crash, hold the dongle's multi-purpose button for 10 seconds at power-on — the bootloader treats that as a "boot the other slot" signal.

Versions

• The current firmware version is shown in the hub's footer and via GET /api/info.
• Release notes live in github.com/emdzej/bimmerz-box/releases.
• Built artefacts are produced by the firmware repo's CI. Download the bimmerz_box.bin from the release page, drop it on the OTA form.