IMHO this is an Android question. Maybe when you search in one of the Android forums you might find an answer.
Actually it's not. Because if it's something about HID then it should be universal. And as I mentioned in my text, I'd no luck finding a solution on Android forums.
Hello alalc_1520441 ,
The Hands-Free Profile (HFP) describes how an audio gateway device can be used to place and receive calls for a hand free device.
The classic Bluetooth ( BR/EDR) supports this profile but the Bluetooth Low Energy (BLE) devices does not support this profile. So, it is not possible to handle the phone calls using any BLE device.
Thanks for your answer Gyan.
Do you have any idea if it's possible to bypass it somehow? I just want to use it as call on/off.