Welcome to the community forum and sorry for the delay.
The tweaking process of pull-up resistors isn’t described in our docs. It’s not used for any standard configurations of the autopilot controller. Could you please share why you need to have access to these resistors? I might help you to find a workaround for your workflow.
Navio2 has internal pull-up resistors; however, it’s hardly possible to access them on the servo rail. We don’t support reconfiguring the internal resistors of Navio2.
You can use GPIO17/18 pins with an internal 47k pull-up to 3.3V. They’re available on the UART port of the device. Navio2 pinout scheme might be of help to you.