I'll try this.Enable parental controls to block updates.
Any other options ?
I think I've found the solution. Turn on the wireless switch. Put your 3DS in sleep mode. Keep it on sleep mode for 5-10 seconds so that it can start downloading (and deleting the previous update.) Then open your 3DS and turn off the wireless switch. There you go! It deleted the previous update and started downloading the new one and you turned the wireless switch off while it was downloading the new update thus making it stop dead in it's tracks. Congratulations, your 3DS will now stop it's bitching.
Has anyone tried this ?