So, some people seem confused, so I'll post some clean-up.
1. Have emunand set up and UNLINKED.
2. US downgrades you to 4.2
3. Both exploits work
4. You need to make a sysNAND backup on 3.0.1 before you downgrade, plus, be safe kids, use protection
I used the 3.0.0 launcher.dat when I did my downgrade