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Updating from a USB key
When the boat has no usable internet link — or during a yard visit, where carrying the file is simply faster than downloading it — an update can be brought to the Brain on a USB stick.
Nothing has to be typed. Plugging the stick in is the whole procedure: the Brain notices it, looks for an update on it, decides whether it is newer than what is running, and installs it if it is.
What you need
- A USB stick the Brain can read: FAT32 or exFAT, which is what a stick formatted on Windows or macOS already is.
- One update file on it, ending in
.raucb, as supplied by MUXEN. Put it at the top level of the stick — it is found in subfolders too, but there is no reason to make it harder to see. - The file exactly as it was given to you. Do not rename it: the name carries the build date, which the Brain uses when the update file itself does not state a version. Do not unzip it, and do not copy it through anything that might alter it.
The Brain accepts an update file only if it was built for a Brain — a file meant for different hardware is refused before anything is written.
The procedure
- Plug the stick into the Brain.
- Wait. The Brain finds the file, checks it and installs it. This takes several minutes — the image is around 2 GB and is written to the internal storage.
- Reboot the Brain when the install has finished.
- Remove the stick.
Nothing on the boat is disturbed during step 2: as with an update from the HMI, the new version is written into the copy of the system software the Brain is not running from. The switch happens at the reboot in step 3, and that is the only moment the screens go down.
If the new version does not come up, the bootloader falls back to the previous one exactly as it does for an update from the HMI. A USB update is no more risky than an over-the-air one.
How the Brain decides
An update file on a stick is not installed just because it is there.
| Situation | What happens |
|---|---|
| The file is older than what is running | ignored |
| The file is the same version and build as what is running | ignored |
| The file is newer | installed |
| The file was built for other hardware | refused, nothing written |
Several .raucb files on the stick | the newest by filename is the one considered |
| The Brain cannot tell what it is currently running | the file is installed |
Versions are compared first, and the build date only settles a tie between two files of the same version. The practical consequence is that a USB key cannot be used to go back to an earlier version. Going backwards is a yard operation with different tooling.
Leaving the same stick plugged in, or plugging it in again after the update, does nothing the second time: the version on it is no longer newer than what the Brain is running.
Did it work?
After the reboot, the update page shows the installed version. If it is the version that was on the stick, the update is done.
One difference from an update over the air is worth knowing: the update server is not told about a USB update. No assignment was involved, so nothing is reported, and the server's idea of what this Brain runs stays where it was until somebody corrects it there. The Brain itself is entirely correct — only the server's record is stale.
If nothing appears to happen at all, or the version does not change, see When an update does not go through.