It all depends on if you're using a rom with apps2sd. And if you flash a rom with apps2sd not available, your phone will either bootloop or go to a black screen and become unresponsive. Only way to fix that is booting into recovery and clearing sd-ext, assuming you did partition your SD card so that you have a main storage, swap (which isn't entirely necessary for the bh2 atm), and an ext-space for apps2sd...or pulling out your sdcard before booting up your phone. The first is easier, and makes it so you can continue using your sdcard, although you lose all apps that are saved in there, whereas the latter will make it so that you cannot used your sdcard when booting up your phone and becomes a hassle.