DSA800 Boot Loader: It is customary for electronic equipment manufacturers to store their Boot Loader in ROM, EROM, ERAM, etc; in a form of Protected Memory. Not necessarily to prevent hacking, but to safe guard it from corruption. Because once corrupted (and it has to be retained for the Life Of The Equipment) the unit is dead in its tracks, and re-installation of firmware isn’t generally possible. So then, > Back To The Factory. That’s why I said the changing the firmware will probably be tricky. The task of the Boot Loader is primarily to just boot up the system firmware upon equipment power up, to check and control firmware updates, changes, and installation methods. Not to prevent alterations of installed firmware. The firmware, its checksum(s), etc, do that job. So the Boot Loader doesn’t itself prevent someone from hacking the Rigol Options.
We know that the Rigol DP800 Series is an exception to using protected memory for the Boot Loader. Because Rigol provided a new Boot Loader along with at least one of its firmware updates.
Hopefully someone can figure out how to go back to a earlier Boot Loader in the DSA815. Although if its protected, and very likely it is, especially in the newer hardware Main Boards, then it may not be easy at all. It would have been very easy for Rigol to add a Boot ROM in the newer boards (v. 7 and above), and then it would be much more difficult to change, But Not Impossible.