Firmware Updates: Complete GuideUpdated 7 days ago

Firmware is the software that runs inside your Combustion tools. This guide covers what it is, how to update it, and what to do when an update does not finish.

Why firmware matters here more than most places

There is a surprising amount of computing power inside a Predictive Thermometer. The onboard processor is what makes all the important calculations, including the predictions, which is why your thermometer keeps working when your phone wanders out of range.

That also means updating it does more than fix bugs. The more cooking data we gather, the better our Predictive Engine gets, and a firmware update is how that improvement reaches the thermometer you already own. Updates have also added whole features, like new cooking predictions and food safety tools, without anyone needing to buy new hardware.

It is close to a free upgrade to something you already have. Worth doing.

Before you start

Install the latest version of the Combustion app from the App Store or Google Play.
Charge every tool you are about to update. A flat battery partway through an update is the most common cause of trouble.
Update one tool at a time, in this order: Predictive Thermometer, then Display, then Booster.
Turn off every tool you are not currently updating. This matters more than people expect, and it is the single biggest factor in updates that run cleanly.
Take the thermometer out of the Booster. A Booster will not update while it is holding a thermometer.

The quick way

When an update is available, the app usually shows a banner at the top of the home screen.

Tap the update banner.
Follow the prompts.
Let it finish without closing the app.
Repeat for the next tool.

Doing it manually

If there is no banner, or you would rather drive it yourself:

Open the Combustion app.
Tap the gear icon for settings.
Tap Update Devices.
Select the tool you want to update.
Wait for it to finish.
Repeat for the next tool.

Recharge each tool after it updates. Updating uses a lot of battery, and the thermometer especially will want topping up before you cook with it.

If an update will not finish

Work through these in order:

Force-close the app and reopen it, then check the status again. It quite often already says up to date.
Restart your phone. iPhones in particular hold onto old Bluetooth connections, and a restart clears them.
Confirm only one Combustion tool is powered on. Hold the button on a Booster for one second to turn it off, and the start button on a Display for one second.
Make sure the app is not also running on another device nearby, such as an iPad. Two instances can compete for the connection.
Keep your phone close to the tool for the whole update.
Force a restart of your phone. This is the step that most often clears a genuinely stuck update, because it flushes the Bluetooth cache that an ordinary restart leaves in place. It will not delete your settings, your accounts, or anything else.

iPhone 8 and newer, including all Face ID models: press and release Volume Up, press and release Volume Down, then press and hold the Side button until the Apple logo appears, about 10 to 15 seconds.
iPhone 7 and 7 Plus: hold Volume Down and the Side button together until the Apple logo appears.
iPhone 6s, SE (1st generation), and earlier: hold the Home button and the On/Off button together until the Apple logo appears.
Android: hold the power button and Volume Down together for about 10 seconds. The exact combination varies by manufacturer, so search for your model if that does not work.

Updates sometimes appear to pause at "Starting" for a while. Give it a few minutes before deciding it has failed.

Firmware Rescue

If an update is interrupted, a device can be left stuck in what is called its bootloader, unresponsive and apparently dead. Interruptions happen for ordinary reasons: the battery ran down, Bluetooth dropped, the app was closed, or the tool got power-cycled at the wrong moment.

The app can now recover these devices by itself. It detects a tool stuck in the bootloader, starts recovery automatically, restores it, and finishes the update that failed.

On iPhone and iPad, this happens automatically. There is nothing to do.

On Android, open the Update Devices screen and leave it open. The app will find the affected tool and begin recovery.

If you have a tool that was left stuck by a failed update some time ago, it can still be rescued. Update to the latest app version, open the app and let it scan, then follow the instructions above for your platform. Recovery can take several minutes, so let it run.

Avoiding failed updates in the first place

Charge the tool fully first.
Update one tool at a time, with everything else switched off.
Keep your phone next to the tool.
Do not close the app while an update is running.
Do not cook with a thermometer that is mid-update.

If a thermometer will not respond after an update

As a last resort, leave the thermometer out of its charger and Booster for 96 hours. This resets it to factory firmware, and you can then redo the update cleanly.

It is a slow fix, but it recovers thermometers that look completely dead.

Firmware version histories

To see exactly what changed and when, each tool has its own history:

Common questions

Can I use someone else's phone to update?

Yes. Almost any iOS or Android device works, and it takes under five minutes. No account is needed, and the phone is not permanently tied to your thermometer.

Do I have to update?

Nothing forces you to, but you will miss prediction improvements and new features, and some newer app functionality expects current firmware. It is worth staying reasonably current.

Why does my Booster refuse to update?

It is almost certainly holding a thermometer. Take the thermometer out and try again.

Still stuck?

If an update still will not complete, email [email protected] with:

Which tool you are updating, and its current firmware version
Your app version, and your phone or tablet model and operating system version
Where in the process it stops, and any message you see
Whether you have tried the 96-hour reset

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