dont think that i get an hardmod managed, because of the soldering. So, i keep fingers crossed that i get my n3ds back without firmware update!
um, the firmware uodate does not remove arm9loaderhax they would have to flash a new signed nand with a clean firm0/firm1 partition to remove it
Yes, unless you got a motherboard problem (which you apparently didn't), then you're safe as most of CFW protect firm0/firm1 partitions (which is where a9lh is stored), so you won't lose it, and if you got a problem like system booting on a black screen, that just means that your cfw is outdated and you need to update/change it for a new one (Because 11.3 broke booting with outdated nfirm system, so many CFW like RxTools don't work on 11.3). But otherwise your installation should be ok and you won't need any downgrade/hardmod.
quick update: unfortunately it is not to much effort for the service to replace the whole motherboard to prevent you from using homebrew
What ? You must mean a9lh and cfw, because homebrew can be launched on lastest firmware of any 3ds so no matter if they replace the mobo or not it just doesn't change the thing.
Right, that link is for SafeHax for 11.3. Follow the guide... https://3ds.guide/homebrew-launcher-(soundhax)
Shouldn't you be going "yayyyyy" ? You can get CFW on it. Pretty sure the guide is being updated, like now. https://3ds.guide