Anyone wrestling with how to change the default input of a full HD Panasonic plasma?
This may also work for recent LCD screens.

Invoke the HOTEL MODE.

Here's how:
Press and hold the -V button on the front or right hand side of the screen, while pressing 3 times (in rapid succession) the AV button on the remote.
Now you see the HOTEL MODE.
Activate it by switching to ON.
Change INITIAL INPUT to whatever you want (like: HDMI1).
You can also change the startup VOL level (like: to Zero) and the MAX. VOL level.

Now you don't need to look at analog snow first and build an elaborate macro to invoke hdmi1 after the screen has completely started up.

Caution:
STAY AWAY FROM REMOTE LOCK AND BUTTON LOCK.
For instance locking the remote will prevent access to the screen (including the Hotel menu) through the remote.

Good Luck!
Barend