You can only boot into emunand via homebrew launcher on system FW 9.2 or below.
On anything below 11.0 you can downgrade to 9.2
On 11.0 you're screwed.
However if you have a9lh you can basically do whatever the hell you want as long as you have FIRM protection enabled.
Essentially yes.
You have control of the system at such a low level you can use haxxxxx to prevent Nintendo from updating your FIRM.
If you have FIRM protection disabled then any update will destroy a9lh.
a9lh loads before the actual firmware loads afaik, so even using a system update would not affect, from what i'm seeing only a new hardware revision would be able to fix a9lh
Because a9lh preverves itself because it lives in the firm partitions which are protected by cfw that is enabled by a9lh , making it pretty much flawless.
Btw op this firm patching/protect that everyone is talking about is enabled by default on luma3ds, the best cfw out there so don't worry about that https://github.com/Plailect/Guide/wiki
a9lh loads before the actual firmware loads afaik, so even using a system update would not affect, from what i'm seeing only a new hardware revision would be able to fix a9lh
New HW revision might not even fully fix the problem... They could, somehow, make it not able to run the 2.1 FW, ofc, but assuming it could still run n3ds FIRMs (again, they might be able to combat this) then there's still nothing they can do, we just need a way to install without the OTP (which has a possibility of becoming a thing, for n3ds at least... However, it's essentially luck based, so I wouldn't put money on it)