I know it's been almost 2 years since anyone has posted on this, but I have a pretty reliable workaround for the input selection problem.
The main issue with not having discrete inputs is that when it get's messed up, you never know what input it is on, so most solutions require multiple button pushes to get to the right input.
There is actually a way to normalize it using the following sequence:
Last <-- this is the key!
Direction (however many number of times below your tuner)
The "Last" button goes to the last tuned channel on the antenna. This is always the first input. From here, you press input, then the down button however many times to get to the right input, then enter.
I programmed this as a sequence then assigned it to a button and called it "Input Fix"
Most of the time the input doesn't change, but when it does get messed up, this button can fix it every time.