Please try below method. If issue continues, please take picture of your Bluetooth module for me.
Devices: mBot or Ranger, Dual Mode Bluetooth module, Windows 10 laptop
Problem: Connect mBot with mBlock 5.1.0 through Bluetooth (based on PC built-in Bluetooth adapter), mBlock 5 can detect mBot and connect to it under Bluetooth 4.0. But it always suggest to do firmware update though we have done already.
Reason: windows 10 system doesn’t support mBot/Ranger earlier Bluetooth version.
Step 1: Install Zadig driver to replace the PC built-in Bluetooth driver. Here is guidance: https://www.mblock.cc/doc/en/part-one-basics/connect-devices.html#3-bluetooth-40-instructions-for-windows-users
Step 2: Download and install test mLink:
Step 3: Open mBlock 5 online version and connect mBot/Ranger: https://ide.mblock.cc/#/
1.The above solution only supports mBlock 5 online version. If you want to use mBlock 5 client version, please try mBlock 5.0.1 and here is download link: https://dl.makeblock.com/mblock5/win32/V5.0.1.exe
2.Once installed Zadig driver, Bluetooth on mBlock 5.1.0 client version is not working any more. If you want to get the Bluetooth feature on mBlock 5.1.0 client version, please refer to the link in step 1 to uninstall the Zadig driver.
3.If you have another Bluetooth module and fails to detect mBot/Ranger under Bluetooth 4, you may also try above solution.