You are right, but I always had the impression that manufacturers turn the blind eye if such hacking is for personal/hobbyist use (or for Rigol this is even marketing strategy ). Hence plenty of threads on this forum on Tek's internal GPIB commands, options EEPROMs, Agilent's binary exe patches or USB booting etc.
The difference is that, at least for brand name kit, these discussions revolve around circumventing the option code protection - which usually means you have to modify the scope or its software (i.e. patching). It didn't include uncovering the system of option keys so that they can be generated yourself, like it was done with the Rigol.
Leaving Rigol aside, I guess the big manufacturers see it different than if you crack their key generation system.
Now if you buy an older Agilent scope (i.e. DSO8k) then the key system is different than for modern scopes. Keysight also no longer sells option keys, so I guess they care little for what people do with these old scopes. However, the key system used on the LeCroy WavePro 7k is the same as for its current scopes, so to some extend they are worried that the information get out in the open.
But then the question is if one user can decipher the key in very short time, can the key system really be considered to be adequately secure?
I wouldn't encourage such tricks in commercial environment and I doubt many people would. As a company you buy new scope, options and then expect good warranty and support.
It's unlikely to work for businesses anyways as the manufacturers have records as to which scope comes with which options so they'd quickly find out if a hacked scope was sent in for repair/calibration.
Also, especially commercial buyers regularly get options thrown in/for free when buying kit anyways.
These hacks are really only interesting for hobbyists.
[TDS7104]
I know, that is why I got interested in LeCroy, they seemed to know the benefits of good PC platform integration in the scope early on (even the old MS-DOS ScopeStation). With dxl's fixed driver it might be even possible to upgrade the motherboard (to some i3/i5), as long as it has PCI slot (or maybe PCIe to PCI adapter) for the interfacing card, right?
In principle, yes. Although I'm not sure how much benefit is there in upgrading the mainboard, as once you upgrade the CPU to a 3.2+GHz Pentium4 (which can be had for a few bucks these days) there is little improvement in performance. And even less so when dxl's front panel driver makes it possible to enable HyperThreading.
TDS7k is obviously not that good, has the custom motherboard (nasty) but often can be had really cheap on the second hand market.
Cheap, I don't know, the ones I saw did fetch much more than I'd be willing to pay for such a scope.
I was also looking at Agilent, things like 54845A, but in tradition with other Agilent scopes it has laughable amounts of memory.
Not all of the old Infiniiums (548xx, DSO8k/80k) have so little memory, some go to 128MB. However, often there are limitations re sample size and sample rate, i.e. the DSO80k that sample at 20/40GSa/s can only use full memory at below 2GSa/s (above that the memory shrinks to a few hundred kpts)
Also, the older 54800s weren't exactly reliable, especially the ones running Win9x. They also have a painfully slow, crude architecture using two graphics adapters employing hardware overlay. The UI is also pretty cramped on the low resolution (640x480) display, and only basic functions can be used without a mouse connected. The DSO8000/80000 Series is much better, as it has an improved architecture, doing away with the crude hardware mixing with two graphics adapters, and the internal display is now an XGA (1024x768) touch screen which means most functions can be used without keyboard and mouse. And the UI itself is pretty horrible, and shows that it has been designed for keyboard and mouse and not touch control.
If you want an Agilent scope that is comparable to the WavePro then you should look at the DSO9k Infiniiums, which is the first proper Windows scope Agilent came up with.