[Q] Can't flash a ROM after total wipe (and recovery) topic

So I installed TWRP, fine. Then I accidentally wiped the whole phone. OK, somehow I managed to get AndroidNow flashed and running....but if I try to flash any other ROM with TWRP I just get stuck in a bootloop (LG logo screen). Yes, I did a factory reset before trying ChupaChups, etc. Yes, wiped the usuals.

Solution? I'd like to try other ROMs or even just go back to the beginning.