Thanks, I installed the latest versions of Atmosphere and Hekate, and updated my Sysnand to 9.1.0 via ChoiDujourNX. It works, but as I said, This update nag keeps showing up whenever I launch a game, even though my Sysnand firmware is already 9.1.0. Going into recovery mode stops the update nag from showing up temporarily, but it'll eventually come back.I suppose this post was made before CFW was updated to support firmware 9.1 but you can now update to the latest firmware without burning fuses. Also ChoiDujourNX automatically enables AutoRCM when it installs a firmware. More precisely, since the firmware installation will overwrite whatever is in BOOT0 AutoRCM or not, it only matters if you enable AutoRCM during the installation or not.
I think this happens because the console thinks it's not on the latest firmware (maybe because I updated via ChoiDujourNX) and automatically downloads the system update from Nintendo servers. But I want to connect to Nintendo servers to play games online on Sysnand. What can be done about this? Should I just update my Sysnand in the normal way?