Cannot change BLE parameters because of echo write error

Which Khadas SBC do you use?

Khadas VIM 3 Pro

Which system do you use? Android, Ubuntu, OOWOW or others?


Which version of system do you use? Khadas official images, self built images, or others?

4.9.241 → vim3-ubuntu-20.04-server-linux-4.9-fenix-1.3-221118-emmc

Please describe your issue below:

I’m trying to update some of the default connection parameters of the bluetooth system on the board which are available under /sys/kernel/debug/bluetooth/hci0. (How to Set Linux BlueZ 5 Connection Parameters for Apple iOS Compatibility - Stack Overflow)

Problem is that I cannot update them due to an echo error. Any suggestions how to update those values?

Post a console log of your issue below:

root@vim3:/sys/kernel/debug/bluetooth/hci0# echo 0 > conn_min_interval
-bash: echo: write error: Invalid argument

Check the driver found that this velue must be 0x0006 < val < 0x0c80, so you can’t set it to 0.

That fixed my issue. My bad. Didn’t read the specifications correctly. For everybody searching the suggested values by Apple can be found here: Technical Q&A QA1931: Using the correct Bluetooth LE Advertising and Connection Parameters for a stable connection