I would definitely try to get a new one, but that'll depend when you bought it. They'll also try to get it repaired instead of giving you a new one, but i'm not updated on German consumer laws, so i can't really tell you what rights you have, but again, time is important here, so you'll need to tell me how long it has been since you bought it. Also, it might be a little tricky to tell them that you were trying to enter fastboot so you could unlock the bootloader and void your warranty, lol. You can either go down that road and act like a pro, or you can act stupid and see how far that takes you
The phone is 6 days old, In germany you have 2 weeks to return anything you buy within 2 weeks from the day of purchase ! , So i guess am still lucky ,