Just think a bit...
First there cannot be "simple hack". If there is no 2nd ADC you cannot make it think it is 4000 by simple model switch in software.
Of course there can.
All the ADC does is get data into sample memory. Nothing downstream from that acquisition step depends on having the ADC present.
There's probably a simple switch in the firmware to choose single or dual ADC acquisition mode.
Firmware is probably identical, selected by something physical on the PCB. Maybe a resistor, maybe even the ADC itself.
Think: Even if you need the second ADC it's still cheaper to buy two HDO1000s than to buy a single HDO4000.
Also there is no interface for active probes. If you enable "4000 mode" software might get confused depending on how it was made.
The HDO4000 is sold with non-active, switchable probes.
https://www.batronix.com/shop/measurement/probes/Rigol-PVP2350.html
Actually, according to you, there is no need for these kinds of scopes at all. It is all a scam by scope salesmen to sell you more expensive scope than you need.
You need to stalk me more closely, you missed posts like these:
https://www.eevblog.com/forum/testgear/should-i-buy-a-rigol-mso5000/msg4481770/#msg4481770
https://www.eevblog.com/forum/testgear/should-i-buy-a-rigol-mso5000/msg4483612/#msg4483612
How do you survive with such reading comprehension? Do you only see green light on the street crossing when it is convenient to you?
Hardware is NOT the same. PCB used is the same, as is most of components. But, and pay attention now, lack of ADC and a contents of FPGA is the key here. I explained it. If there is no second ADC, you need to reassemble data differently. What do you think ADC data ends up magically where it needs to be by magic wand of Harry Potter? FPGA (Field Programable Gate Array) is basically logic block where you define internal "schematics" (logic functions and interconnect really) by bitstream. It is virtual hardware. You change something inside and your PCB suddenly becomes quite different hardware.
Maybe Rigol deliberately and with additional effort created firmware that can work in any combination and with a simple hack. Maybe they did. Maybe they didn't really know how they are going to release it (in what combinations) so they did an really universal one. Maybe.
If not, what I said stands. If they did, then it will indeed be great news for hackers.
Or maybe not.
What is really better with 4000? Additional ADC, better BW, 50Ω and active probes. Right there is several thousands of dollars worth of difference according to Rigol.
If I don't have active probes and additional ADC what is left to hack? Nothing really. 50Ω inputs. For usual 12bit work (analog stuff, power etc) 200 Mhz is mostly enough. Even for pro work. In fact only thing I would like if they enabled would be 50Ω on HDO1000. So hacking, meh.. If It proves to be good working scope without software problems, just buy HDO1000. If someone makes a hack, then just make a hack from HDO1000 70MHz to HDO1000 200MHz and call it a day.
As for this statement :
************************************************************
Think: Even if you need the second ADC it's still cheaper to buy two HDO1000s than to buy a single HDO4000.
**********************************************************WTF does that even mean? Seriously, how does that work? What do you mean by it?
Also, do you really don't know what active probe interface means? I think you do, and this is a deliberate misdirect.
And me stalking you? LOL, we all know who is a stalker here..
And those two posts just show how you have no shame. Since quite some time now you keep repeating this "amplifier fix" nonsense as a reason why scopes with low noise, high resolution and high sensitivity are not better, with specific attacks on single brand. And after Rigol releases scope that specifically targets that, and after you have been called out by more members here to show and demonstrate your claims, then overnight you switch the side and now you pretend you didn't say it.
Which might not be a bad thing, maybe you finally learned you were wrong and corrected your opinion. But for that to happen, you need to say it out loud that you were wrong and that you finally get it now and that you apologize to all for wasting their time. And by that I mean not to me, but others..