RBgrid

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What happens if the firmware update stops halfway

  • Tested on firmware v1.1.6
  • Getting started

An over-the-air update of a box in your fuse board sounds like the kind of thing that can go badly. So here is the mechanism first, because it is the answer to the fear:

The new firmware is written to a spare slot while the hub keeps running on the old one. The switch happens only after the whole file has arrived and passed its checks. Lose power or lose the Wi-Fi halfway and the running firmware is untouched — the hub comes back on the version it already had, and you install again. On our bench an upload cut off at 377 KB of 1,650 KB did exactly that, and the hub log said so in as many words: running image intact.

And if the new firmware is written but doesn't start, the hub goes back to the previous one by itself. Two slots, one of them always known to work.

There is one minute in the process where a person can undo it, and that is the only part of this page worth memorising.

First: a fresh restore point

The firmware and your settings are separate things. An update keeps your settings; a restore point is insurance against everything else, and it takes one press.

Settings → Restore point → Save restore point. It holds six files — settings, hardware, points, tariffs, time and modules — as they are at that moment. There is one restore point on the hub: a new save replaces the old. Restore and restart brings it back, and the hub is up again in 20–30 seconds.

Two things it does not hold, and both matter if you are counting on it:

  • Not your history. Restoring writes only those six settings files; measurement records and lifetime totals are untouched. (Measured: 71 hourly records byte-identical either side of a restore.)
  • Not your access. The API token, the Wi-Fi network and password, the access-point password, the browser-access (CORS) origins and the MQTT broker address are outside the restore point — neither saved nor rolled back.

Save it immediately before you update, not weeks earlier. It restores the hub as it was when saved, so an old point brings back an old layout — the points you have since changed, the tariff you have since fixed.

A restore point saved on v1.1.5 restored cleanly on a hub updated to v1.1.6 — measured, all six files, no complaints. There is no version check; the hub won't refuse an older point. Other version pairs haven't been tested, which is the real reason to save a fresh one rather than to trust an old one.

The file

From the release, you want main_release.bin and nothing else. The other three files in the release are for a fresh USB flash and won't do here.

The web app is not in that file. It ships as its own kit, rbgrid-ui_<version>.zip, installed afterwards — see the end of this page. Two files, two steps, and keeping them straight is the most common way to get confused about what you just updated.

What you will actually see

Settings → Hub firmware. The panel opens with what you have now:

Now: version 1.1.5 · build Nov 6 2026 16:38:17 · image 3ecbbfde

Choose the file, and it tells you what is in it before anything is sent — size, version, build, and the framework it was built with. The checks run here too: a file that isn't a firmware image is refused, so is one without a description, and so is firmware for a different device ("This is another device's firmware, not the hub's"). Pick the build you already run and it says "This build is already installed. No need to update." — Install stays available, and reinstalling works.

Press Install and confirm. The dialog is worth reading once, because it describes the whole sequence:

Update the hub firmware? The hub takes the file, restarts (offline for about half a minute) and confirms the new firmware a minute after it starts. Don't power the hub off until it's done.

Then the panel narrates it, and nothing is silent:

  1. Sending the file… 6 % … 100 % — about 30 seconds on our bench over Wi-Fi.
  2. The hub wrote the firmware and is restarting…
  3. The hub is back. Waiting for the new firmware to confirm (about a minute)…
  4. Done: the hub runs the new firmware — version 1.1.6, build Nov 6 2026 21:28:48.

Start to finish, about 1 minute 40 seconds on the bench — well inside the three minutes the app waits before it gives up. Your own time depends on your Wi-Fi; treat ours as the shape, not the figure. The header then reads the new version, and that is the update done.

The minute that matters

Between step 3 and step 4 the new firmware is installed but not yet confirmed. A restart inside that window — by hand, or by pulling the power — rolls the hub back to the firmware it had before. Everything will look as though the update simply didn't happen.

So: don't power the hub off, and don't restart it, until the panel says Done. That is the single thing this page exists to tell you.

You are unlikely to meet the hub's own refusal in that window, and it is worth knowing why: Done appears only after the confirm, so by the time the panel offers you anything, the minute has passed. It shows up if a second browser tab, another device or a script tries to install while the first one is still waiting:

Failed: The hub is still confirming the firmware installed less than a minute ago. Try again in about a minute.

Nothing is wrong when you see that. Wait a minute and install again. (The message itself is firmware v1.1.6 with its matching app; on v1.1.5 and earlier the same situation failed with a generic error.)

When it doesn't take

  • The new firmware didn't start. The hub returns to the previous one on its own and the app tells you: "The new firmware didn't start — the hub went back to the previous one. Details in 'Events → Hub log'." The hub log is on the Log tab. → Events
  • The hub didn't come back within three minutes. The app stops waiting and says so. Check that the hub is powered and on your network, then reload the app and look at the version in the panel header: it will tell you which firmware you are on.
  • Power or the connection went during the upload. The hub stays on the firmware it had. Install again.

In each case the restore point is the second net, and it is for your settings — not for the firmware, which has its own.

Going back to an older release

You can. The hub doesn't block it: installing an older main_release.bin works the same way as a newer one, and it was measured going from v1.1.6 back to v1.1.5.

What you get with it is that release's behaviour, bugs included — a hub below v1.1.6, for instance, can wipe your NTP servers when you save the time zone, which v1.1.6 fixed.

⚠️ And one rule that isn't optional: if your three-phase input is metered one point per phase, switch it back to one point before installing anything older than v1.1.5. Older firmware handles one supply point only. → Your three-phase supply is being measured on one phase

What an update keeps

Wi-Fi, settings, points, tariff, tokens, history and the installed web app are all kept. The modules keep counting while it happens — the update is the hub's business, not the meters'.

Afterwards, install the release's matching rbgrid-ui_<version>.zip so the app you open is the one built for the firmware you now run. Several of the things a release changes live in the app rather than the firmware, and until the kit is installed you are looking at the old app over the new hub.

One last thing, because it is the question behind the question: the hub doesn't fetch firmware by itself. There is no background download, no "update available" nag and nothing that applies overnight. It updates when a person chooses a file and presses Install, and never otherwise.

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