What I kinda fail to understand though, is why they have incorporated at least some part of hardware driver into bootloader that is designed to not be user-replaceable.
Whatever the problem is, it's not caused by the bootloader.
Plenty of people have that particular bootloader and don't have the problem.
Bad design IMO.
Not really. If all the bootloader does is load the main firmware into memory, then ... what's to replace?
"Bad design" would be system that can be bricked by users trying to update their bootloader when there's no need.
Er.... no. Every case that I know about of a scope that can be "locked up" due to the Freeze Bug is running Boot Version 0.0.1.2, no matter what "firmware" the scope is running. As you can see poorchava has the latest "firmware" revision but the older Boot Version, and he is able to reproduce the Freeze Bug. It _may_ be the case that _some_ scopes with Boot Version 0.0.1.2 do not have the Freeze Bug, but I am still not convinced even of that much.
"Plenty of people have that particular bootloader and don't have the problem." .... the Poll indicates that nearly half the people who tried it were indeed able to get their scopes to freeze. But....
Many people did not seem to be able to follow the precise instructions, and some people have contaminated the Poll in that thread by reporting results from other models of the scope, such as 1074z and MSO versions and actual 1104z scopes. When the thread and poll was started we did not yet know how to display the full System Information screen that indicated which Boot Version was in use so we are missing data, but in every case that I am aware of where we _do_ have the full data, the scopes which freeze are running Boot Version 0.0.1.2.
And you and I have no idea just what the Boot Version actually does. A reasonable software design would have it just "load the main firmware from memory" but is anyone really confident that Rigol's software is "reasonable" at this point?
Meanwhile -- if you know of a DS1054Z scope that is subject to the Freeze Bug but does NOT have Boot Version 0.0.1.2 installed, please report it. And if you know of one that DOES have Boot Version 0.0.1.2 installed but does NOT have the Freeze Bug, please let me know and I'll send a .stp setup file that contains all the conditions so that scope can be tested without having to worry whether the user actually did try the proper combination of conditions. Until we have such data, I'll continue to believe that the Freeze Bug is associated with Boot Version 0.0.1.2, since all the data we _do_ have -- including poorchava's test -- supports that conclusion. It may be the case that some combination of Boot Version 0.0.1.2 plus some hardware instability is required for the Freeze Bug, making the Boot Version 0.0.1.2 a _necessary_ condition but not a _sufficient_ one.