Android usb serial setting custom baud rate

Question

I know how to set standard baud rates with the method UsbDeviceConnection.controlTransfer().
But how can I set a non standard baud rate, like 3000000 or 4000000?
This topic is little documented and I don't know how to do it.

Answer 1

I found how to do it:

controlTransfer(65, 30, 0, 0, new byte[]{-64, -58, 45, 0}, 0, 4, 5000);

(this is for 3000000 bps).
I found it by adding logs to the method controlTransfer() (and building the ROM), and using the apk Serial USB Terminal from google play.