While MAKCU is running, press the LEFT button 4 times within 2 seconds.
The LED next to USB 1 will flash to show the current baud rate:
4 flashes = 4 Mbps
1 flash = 115k
Press the button again to cycle between baud rates.
This is the only way to permanently save the baud rate setting.
If you see 4 flashes on boot but need 115k:
Press the LEFT button 4 times within 2 seconds to switch.
Do NOT change the baud rate in Windows Device Manager.
Windows settings have zero effect on MAKCU’s actual speed.
MAKCU manages its baud rate internally.
Windows baud rate settings are completely ignored.
You can safely leave them as-is.
If you see this error:
You are on V2 firmware.
To fix:
Option 1: Reflash the firmware using the flashing guide. Option 2: While MAKCU is running, press the LEFT button once to switch baud rate. This change saves permanently.
If the mouse is not moving during testing:
Check the list of known working mice: https://pastebin.com/ukRq383f
If your mouse is not on the list, assume it is incompatible with MAKCU.
Recommendations:
Swap to a confirmed working mouse.
Avoid unbranded AliExpress / Temu mice.
Use known brand gaming mice.
If you receive a “Failed to write serial” error:
Make sure you are using the SECOND PC.
Swap USB ports.
If the issue continues, replace the USB-A to USB-A cable.
Low-quality cables are a common cause of this issue.
If you’re still experiencing issues after following this guide, open a support ticket in Discord with:
A photo of your wiring
A screenshot of the error
Your firmware version
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