I wonder how easily the firmware can be downgraded (or downgraded) to remove that behaviour. Though as noted in the sibling thread, it's more likely easier to crop the video output.
Distinctly non-trivial. The receiver software is cryptographically signed and is heavily integrated with the conditional access system securing the underlying broadcast.
I'm only aware of one time that a legitimate box was encouraged to run a lightly-patched version of the software, and that involved a JTAG-type attack on a specific model of set top box. I believe that lesson has been learned in current models.
In Germany, almost no one uses Sky, and those who do, almost completely run patched boxes. It’s even easy to use one single subscription on thousands of boxes at the same time.
It'd probably be much easier to just blur the area of the image where they put it to be honest, I've seen this on streams before, they just blur the bottom corner where the number would show up.
Although the position of the number is (obviously) under the control of the platform operator, so could appear anywhere, for any amount of time, if they were so minded.
I wouldn't like to bet against the number appearing right in the centre of the screen for a fraction of a second, if there were any particularly high-value programming being illegally streamed.
I'm only aware of one time that a legitimate box was encouraged to run a lightly-patched version of the software, and that involved a JTAG-type attack on a specific model of set top box. I believe that lesson has been learned in current models.