OK, About to take the plunge and flash my first ROM. I'm using SPRecovery and I understand that I rename the download to "update.zip" before I put it on the root of my SD card. However, I already have a file called "update.zip" on my SD from when I rooted my phone. Do I just replace the file? If so, will it cause me to lose anything? I'm being very cautious cause I'm a total N00B and I really don't want to hassle w/ a bricked phone!