BIBA40 OWNER SUPPORT
Biba40 Help
Start here for everyday setup, Bluetooth controls, keymap customization, and solutions to common problems. Assembly instructions and development files remain available on GitHub.
QUICK START
Getting started
These steps apply to an assembled Biba40 with firmware already installed. DIY kit builders should use the full build guide linked under Resources.
Charge both halves
Connect each half to USB power. Both halves contain their own controller and battery, so each side charges separately.
Power on the left half first
Turn on the left half first, then turn on the right half. The left half is the central, or master, side. It receives input from the right half and communicates with your computer, tablet, or phone.
Pair with your device
Open Bluetooth settings on your computer, tablet, or phone and select the Biba40 when it appears.
Test both halves
Open a text field and test keys on both sides. If only one half responds, use the troubleshooting section below.
Five Bluetooth profiles are available. You can pair the Biba40 with up to five devices and switch between them from the Adjust layer.
DEFAULT KEYMAP
Controls and layers
The standard letter layer stays simple. Hold a layer key to temporarily access numbers, symbols, Bluetooth controls, function keys, or mouse controls.
| Layer | How to access it | What it contains |
|---|---|---|
| Default | Normal typing | Letters, modifiers, arrows, spaces, and common punctuation |
| Lower | Hold the Lower key | Number row, number pad, volume controls, and left-side bootloader access |
| Raise | Hold the Raise key | Symbols, brackets, delete, caps lock, and right-side bootloader access |
| Adjust | Hold Lower and Raise together | Bluetooth profiles, pairing reset, USB or Bluetooth output, and soft power off |
| Function | Hold the bottom-left Function key | F1 through F12, mouse controls, scrolling, and ZMK Studio unlock |
Visual keymap guide
Open a layer below to see the physical key positions. Outlined keys show the key or keys being held to reach that layer. Blank keys do not perform a separate action on that layer.
Default layer
Lower layer: numbers, number pad, and volume
Raise layer: symbols and navigation
Adjust layer: Bluetooth and output controls
Function layer: F keys, mouse controls, and Studio
Hold FN to use this layer. Studio Unlock is in the physical Ctrl position. The mouse controls are grouped on the lower-right side of the keyboard.
Bluetooth controls
Hold Lower + Raise to open the Adjust layer, then use these physical keys while continuing to hold both layer keys:
| Key position | Action |
|---|---|
| Top-left key, normally Esc | Clear the currently selected Bluetooth pairing |
| Q, W, E, R, or T position | Select Bluetooth profile 1, 2, 3, 4, or 5 |
| Tab position | Move to the next Bluetooth profile |
| Shift position | Move to the previous Bluetooth profile |
| Z position | Clear all stored Bluetooth pairings |
| A position | Toggle between USB and Bluetooth output |
| S position | Select USB output |
| D position | Select Bluetooth output |
MAKE IT YOURS
Customizing the keymap
You do not need to understand the source code to make basic key changes. Start with ZMK Studio. Use the web-based Keymap Editor and GitHub workflow when you need deeper control.
ZMK Studio
Best for approachable keymap changes. Connect the left half only to your computer with a USB data cable. The left half is the central side and is the half configured to communicate with ZMK Studio.
Open Studio in Chrome or Edge, choose USB, select the Biba40, and unlock Studio from the Function layer when prompted.
Keymap Editor
Best for advanced layer and behavior changes. This open-source editor was created by Nick Coutsos. It connects to a GitHub configuration, saves keymap changes back to GitHub, and starts a new firmware build.
After the build finishes, download the firmware files from GitHub Actions and flash the appropriate file to each half. Review the editor and GitHub instructions before committing changes.
COMMON PROBLEMS
Troubleshooting
Open the problem that most closely matches what you are seeing.
The Biba40 does not appear in Bluetooth settings
- Confirm that both halves are charged and powered on.
- Select a different Bluetooth profile using the Adjust layer.
- Clear the current profile using Lower + Raise + the top-left key.
- Remove any old Biba40 entry from your device’s Bluetooth settings.
- Search for the keyboard again and complete pairing.
Only one half is typing
- Charge both halves separately.
- Power both halves off, wait a few seconds, and turn them back on.
- Keep the two halves close together during the first test.
- If the problem continues, contact Biba Keyboards before resetting or flashing firmware.
The keyboard is connected but keys are not typing
- Confirm that the correct Bluetooth profile is selected.
- On the Adjust layer, use the D position to select Bluetooth output.
- If connected by USB, use the S position to select USB output.
- Release all layer keys and test again in a plain text field.
A key produces the wrong character or function
- Release Lower, Raise, and Function to return to the Default layer.
- Check the active language and keyboard layout in your operating system.
- If the keymap was changed, inspect it in ZMK Studio or Keymap Editor.
I need to enter the bootloader
Use the bootloader only when you are ready to install verified firmware.
- Left half: hold Lower and press the bottom-left Function key.
- Right half: hold Raise and press the bottom-right Arrow key.
Each half is flashed separately. If you are unsure which firmware file to use, contact Biba Keyboards first.
I want to clear every Bluetooth pairing
Hold Lower and Raise together, then press the key in the Z position. This clears all five stored Bluetooth profiles. You will need to remove the old keyboard entry from each host device and pair it again.
LINKS & DOWNLOADS
Resources
Biba40 GitHub
Firmware source, design files, configuration, and the current default keymap.
Biba40 V2 Build Guide
Assembly documentation for DIY kit builders.
ZMK Documentation
Official documentation for the firmware that powers the Biba40.
About the Biba40
Learn why the Biba40 was created and what makes it different.
STILL NEED HELP?
Send me a message.
Include what device you are connecting to, which half is affected, and what you have already tried.
Contact Biba Keyboards