Originally Posted by DeezNotes
All ROMs should always wipe /system. A "patch" won't wipe /system. When he says no wipe required, that's referring to a /data wipe. Things have always been this way. It doesn't make sense otherwise.
Correct. Wipe always user data. /system will be formatted every single time you flash unless a package is explicitly labeled a patch.
Originally Posted by Catnap
Give me a break- if, for instance, 3 APKs have been altered and they're the same name as before, there is absolutely no point in wiping the entire partition. They'll be overwritten.
I'm not saying that's what's happened here, but it is not necessary to always wipe /system.
It is necessary. People apply all kinds of changes to /system, via mods, addons, etc. Formatting system and flashing all contents makes sure you are in an absolute, known state.
Wipe has always referred to *user* data. When you're flashing a ROM, every partition other than /data and /sdcard is fair game. No ROM should ever touch the two of those. As for /system, /cache, boot, etc, never assume they will persist when you flash anything.