MX Keys firmware is updated with Logi Options+, Logitech's software: it detects the keyboard, offers the new version and installs it. Logitech states that its older Firmware Update Tool is no longer maintained. An interrupted update (cable unplugged, flat battery, software closed halfway) can leave the keyboard unresponsive; most of the time, running the update again under the right conditions brings it back.
How to update MX Keys firmware
Install Logi Options+ from Logitech's website, connect the keyboard, then open its page in the software: when a newer version exists for your keyboard, Logi Options+ offers it and installs it. Before starting, charge the keyboard, plug it in over USB-C if you can, and do not close the software until it has finished. Logitech publishes the list of versions and what each one fixes on its support site.
Diagnosis
A keyboard stuck by an update shows three signs: the fault appeared right after the update, the keyboard no longer responds over Bluetooth or through the receiver, and Logi Options+ reports it as a device in error or no longer recognises it. If the keyboard was already dead before the update, or shows no reaction at all once plugged in over USB-C, the cause is more likely the battery or the motherboard: see the guide "MX Keys won't turn on".
How to fix it
- 1
Plug the keyboard straight into the computer over USB-C (not through a hub) and let it charge for a few minutes.
- 2
Switch the keyboard off and on with its power switch, then restart Logi Options+.
- 3
If Logi Options+ recognises the keyboard, run the update again from its page and let it finish, without unplugging or closing the software.
- 4
If the keyboard stays silent, try from another computer, then contact Logitech support: a keyboard still under warranty may be covered.
FAQ
How do I avoid bricking an MX Keys during an update?
Charge the keyboard before you start, keep it plugged in over USB-C during the update if you can, and do not close Logi Options+ before the completion message. Avoid starting an update on a computer that is about to go to sleep.
Do I need Logi Options+ to update the MX Keys?
Yes: it is the tool Logitech recommends for updating its recent keyboards. The keyboard types without it, but it is what installs new firmware versions.
Where can I see what an update changes?
Logitech publishes the MX Keys firmware release notes on its support site, listing for each version the issues it fixes (stuck keys, connection, battery life…).
Updating an MX Keys is done from Logi Options+, with the keyboard charged and plugged in. If an update was interrupted, run it again under those conditions before assuming a hardware fault; beyond that, Logitech support is the contact for a keyboard under warranty.