I couldn't get this to work on my 9.9.0-25E O3DS. After changing the date and time the update message still always appears as soon as the browser splash screen fades so I couldn't even get to the browser settings to do step 2. I did a lot of googling and tried all the suggestions I found (changing DNS, toggling wifi, deleting connections, opening browser quickly after a reboot, scanning QR codes, tethering to phone, formatting the system) in various combinations, but nothing made any difference.
Edit: ...and now making this post I double check my browser version and I realise I must've done a cart update as it should be 9.9.0-26E. Now that was a dumb waste of a couple of hours >_<