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Buttons and LEDs

SliceMK wireless keyboard PCBs and dongles have a number of buttons and LEDs.

  • Reset button
  • User button
  • Charging LED
  • Indicator LEDs

The Raytac Dongle has a user button but no reset button.

Keyboard PCBs have both a reset button and a user button. If you look straight at the USB C port with the keyboard and keycaps facing up:

  • The reset button is on the right of the USB C port.
  • The user button is on the left of the USB C port.

To help you remember which button is which, remember that right and reset are both 5-letter words that start with the letter r.

Reset Button

The reset button functionality is controlled by the bootloader.

  • Pressing the reset button exactly once will reboot the device.
  • Pressing the reset button twice within 500ms will place the device in bootloader mode.

User Button (Dongles)

On dongles, the user button is equivalent to the &bootloader key. Pressing it once will place the device in bootloader mode.


If you are unable to enter bootloader mode by pressing the user button, the firmware may have crashed unexpected. An alternative method for entering bootloader mode is to unplug the dongle, hold the button, and plug the dongle in without releasing the button.

User Button (Keyboard Halves)

On keyboard halves, the user button will put the keyboard in "system off" state. This is useful for preventing the keys from being pressed when transporting the keyboard, for example.

Once the keyboard is off, pressing the reset button will turn it back on.


When a peripheral half off is turned off, the LED/LEDs will activate for one second.

However when a central half (the left half in a dongleless setup) is turned off, there is currently no LED feedback. This is a temporary limitation and will change in the future. You can still confirm that the keyboard half has turned off by checking that your devices are no longer connected.

Keyboard Charging LED

All keyboard PCBs have a blue LED to indicate charging status.


USB is not connected and the keyboard is running on battery power.

SolidThe battery is currently charging via USB.

If the LED is dim and the brightness is constant, battery is full and charging has completed. If LED is dim but pulsing once a second, please check that the battery is properly connected.

Keyboard/Dongle Indicator LEDs

  • Newer keyboard PCBs have four RGB "underglow" LEDs.
  • The Raytac Dongle has a single blue "legacy" LED.
  • Older keyboard PCBs have a single red "legacy" LED.
RGB LEDLegacy LEDDescription
Brief redBriefThe device has reset and firmware is starting.
Solid greenSlow pulses

This indicates that the device is in bootloader mode. The connected computer will display a virtual drive for updating the device firmware.

Solid redRapid blinks

This can indicate one of several things:

  • If you are attempting to enter bootloader mode, the device is unable to detect the USB connection. Please try a different USB cable, flipping the USB C port, and/or a different USB port.
  • If you just copied a UF2 firmware file to the virtual drive, then the device is in the process of updating the firmware. Please keep the device connected and wait for flashing to complete (LED will turn off).
Solid WhiteSolid

This indicates that the keyboard testing logic failed, possibly due to a hardware issue. Please get in touch for additional troubleshooting instructions.