Even though A9LH is great, it's not the answer to every question.
Hi, I don't want to accidentaly update my 3DS. So I was wondering if you could get rid of the pesky update notification permanently?
Thanks in advance.
No, there's no permanent way of getting rid of them, per-se, but you can take preventative measures:
1.
(DO NOT DO THIS IF YOU HAVE ARM9LOADERHAX, SAFE MODE IS DANGEROUS THERE) If you've got the update nag on sysNAND, boot into Safe Mode (hold L, R, Up on the dpad, and A while booting), then hit cancel so it'll delete the update nag.
2. After that use the TubeHax DNS so that it'll prevent the 3DS from downloading future system updates.
If you have an update nag on emuNAND, the most sensible option is to make a backup of your emuNAND (just in case) and then update to the latest firmware while inside emuNAND. As of this moment in time, it's safe to have emuNAND on the latest firmware.