BOOX Note Air 4 C · Troubleshooting
The BOOX Note Air 4 C pen isn't writing or is lagging
The pen makes no mark, skips, lags behind your hand, or the side button does nothing. Most cases are a worn tip, a software hang, or a setting.
Symptoms
- The pen makes no mark on the screen at all.
- Lines skip, break up, or only register when you press hard.
- The ink appears a moment behind the pen tip.
- The ink lands a few millimetres away from where the tip touches.
- The pen's side button does nothing.
Before you start
- The pen has no battery and needs no charging or pairing — if it writes at all, it is talking to the device.
- Check whether the pen came with spare tips and a tip-removal ring.
- Note whether the problem is everywhere or only in one app.
- None of these steps erase notebooks or books.
Which fix do you need?
What is the pen doing?
- No mark anywhere, or the device does not react to the pen Restart, then test in a fresh notebook
- It skips, breaks up, or needs hard pressure The tip is worn — replace it
- The ink lags behind the tip Restart and lower the refresh load
- The ink lands away from the tip Re-run pen calibration
- The side button does not work Check pen settings and firmware
Most common cause
Skipping or "press hard to write" is almost always a worn pen tip — they are consumable. No marks at all, or lag, is usually a software hang that a restart clears. Ink landing off the tip is a calibration issue. The side button not working is a settings or firmware issue.
Fixes
Fix 1 Restart the device and test in a fresh notebook
A pen that suddenly makes no marks, or writes with lag, is almost always a software hang rather than a hardware fault. A restart clears it.
- Restart the Note Air 4 C from the control centre or by holding the power button for about 30 seconds.
- After it boots, open BOOX Notes, make a new notebook, and try writing near the centre of the screen.
- If the centre works but the edges do not, the problem is likely the tip (Fix 2), not the software.
- If one specific app will not accept the pen but BOOX Notes does, that app lacks proper stylus support — use BOOX Notes or NeoReader for markup.
Fix 2 Replace the pen tip
Pen tips are a wear part. As one flattens it stops making reliable contact, which shows as skipping, broken lines, or needing to bear down. A fresh tip usually fixes it completely.
- Use the small removal ring or tool from the box (or fine tweezers) to grip the tip and pull it straight out.
- Push a new tip straight in until it seats. It should sit flush and not wobble.
- Test on a notebook page. Writing should feel light again and lines should be unbroken.
- Order more tips when you are down to your last one. BOOX sells felt and POM tip packs; textured "paper-like" screen protectors wear tips faster.
Fix 3 Re-run calibration and check the side button
If ink lands away from the tip, the digitiser calibration has drifted. The side button is a software assignment that can be off or lost after an update.
- Open Settings, then the pen or handwriting section, and run "calibrate". Tap the targets carefully with the pen held the way you normally write.
- In the same section, check the side-button action is set to something (for example "eraser") and not "off".
- Make sure the firmware is current, from Settings, then "Firmware Update" — pen behaviour has been fixed in past updates.
- Restart and test again. If ink still lands off the tip after calibration and a firmware check, contact BOOX support.
Undo / recovery
None of these steps touch your content. If a restart, a tip change and calibration do not help and the pen still will not write anywhere, the pen or the digitiser may be faulty — contact BOOX support, and export important notebooks as PDF in the meantime.
Related guides
If the pen skips or needs pressure, replace the tip first — it is the answer most of the time and takes a minute. If it makes no marks at all or lags, restart the device before assuming anything is broken. Ink landing off the tip is a calibration fix, not a fault.