Thanks to abhipati, Inflated Titan, and others. I had a number of problems flashing my ROM after using the newly created 2.20 root method (woohoo! I was so close to selling my HOX and getting a used Gnex), but your answers to noobs' questions helped me out a lot. Thanks!
I have a question about TWRP for people that rooted using the new exploit for 2.20: will restoring a backup work for us if the kernel is different?
Say someone installed CM10 and made a full backup in TWRP. Then, they wanted to try a ROM with an OCed custom kernel, so they flashed the boot.img of the new ROM and installed the ROM in recovery.
But, if they were to switch back to CM10, they have the CM10 backup ready to go - but instead of doing a restore entirely in TWRP, they would first have to flash the CM10 boot.img, and THEN restore their CM10 backup through TWRP, correct?