Great news that the hack is working on Dave's unit. But remember that he has the full list of software keys enabled.
It might be that the resistors allow the system to know the
capabilities of the scope's hardware, but the final decision of enabling and disabling an upgradable feature could very well still be up to software licence keys. That would be at least how i would design such a product feature.
So perhaps Dave's scope is not the best scope to verify all these upgrades on... But still good news that a 100MHz enabled bandwidth scope can be upgraded to a 200MHz+ model