I bricked it, and I managed to recover after some 18 hours of painful trial and error. So someone sent me a tweet showing how cool is the retro interface so I thought why the hell not, I've changed dates on phones and PCs many times before. I wasn't thinking, until I pressed reboot and said "oh shit I shoulda verified the easteregg on google first!" And I fell for it. Long story short. My iPhone6 was freshly charged on my table when I did this. I read all the 3 methods on reddit and youtube.

So plan A it is: I tried to let it reboot to drain the batt, even put it in the freezer a couple times to speed it up. After it quit rebooting and got to the low batt sign, I kept pressing the sleep button until nothing came up on screen to make sure it's fully drained. Then I plug in the charger and waited a few minutes to power it up. Nope, didn't work, still cycling between Apple logo and the spinning wheel forever.

T+3 hrs - Plan B. I went for the DFU restore and downloaded iOS9.2.1, took a while to download all of 1.8gb. iTunes went thru the motion and the phone restarted, it got stuck at Apple logo with the progress bar at 20%. Waited an hour, no progress, tried DFU restore again. Didn't work. Decided to leave it to overnight and see if it progress beyond 20%. Didn't work. Tried again in the morning, still stuck at 20% for 3 hours, obviously DFU didn't work.

T+15 - Reading up on other updates in reddit, I guess I've no choice but to go Plan C as a last resort -- opening up the battery. Ran to the local DIY store and bought me a set of smartphone toolkit. Opened the phone right up, remove the battery terminals for few minutes, plug it back in. Walla!!! It booted right up. I lost all the data but no worries, everything is backed up to iCloud just about 24 hrs ago so I'm now waiting for the restore from iCloud to complete.