Alright, so I should admit that I didn't really find a way to fully
bypass a hyperban. Well, I did... but it's very temporary, and you'd have to do it every time you reboot. This will also only work for Nintendo Network ID-related services, no online stuff until some other day. It's otherwise pretty simple though, so here's how I did it, I guess.
- Download the latest NTR CFW, and get this plugin.
- Start up your 3DS, and launch NTR CFW.
- Hit X+Y on the home menu, go down to 'Process explorer', and get to PID 21. Edit: PID 22 for New 3DS users
- Use the touch screen scrollbar (or anything else) to get to 0x00117636.
Here, you should see "X-Nintendo-Device-ID". Use the editor to change that to literally anything else, like "X-Nintendo-Dedede-ID". (X/Y is up/down when changing bytes)
- Scroll down a bit more to find "X-Nintendo-FPD-Version", it was at 0x0011776E for me. Change that to "X-Nintendo-Device-ID; this is how you're going to actually make a difference. (Nintendo's servers don't actually care about your FPD version or Dedede ID; they track bans by the Device ID, and this is how we're changing it, since the actual device ID is nowhere to be found in the RAM.)
- There's four ASCII zeroes right before X-Nintendo-FPD-Version; this is where it comes from. Change this to whatever you want, it really doesn't matter as long as everyone isn't using "0000" as a deviceID.
- Do whatever until you reboot or close System Settings.
This isn't really the best method, and is only a proof-of-concept really. But hey, I had a Sunday deadline, and I had to show something. Maybe this could be made easier using an NTR plugin that does this directly, or maybe even something that could spoof the deviceID itself? Who knows?
I'm sorry if this isn't what you wanted. I'll go back into hibernation now.