Before installing or flash a new rom or custom rom, It is usually done a deleted (wipe) partial or full erase (full wipe). This is done from the recovery, either CWM or TWRP. When you are installing a new rom the creator tells you to do to make everything work well.
If you want to install a new rom, copy the zip or zips into the SD before entering the recovery.
Desde o ClockWorkMod CWM Recovery:
for use, the volume keys are used + Y – and the power button to select option
– Backup and restore: Important before changing rom. a backup of your rom ago, data and everything as you before doing anything if something goes wrong then, restore and continue as tapeworms all.
– install zip from sdcard – choose zip from sdcard : You choose the ROM zip file to install the new rom.
– Wipe Data/ Factory reset: Typically always do this when you go to install a new rom. What it does is delete the data stored in the internal memory of all installed / Resets to the initial mode rom factory
– Wipe cache partition: Deletes all stored data while using the current rom
Mounts and storage
– Format SDcard: removes everything you have on your SD (never do that unless you want to clean all that you have on your external memory card).
– Format System: You remove current rom, forcing you to flash the new rom before restarting, because with this you run out of operating system.
– Format cache y Data: Deletes cache data and rom
– Wipe dalvik cache: Highly recommended to change rom, deletes files generated by applications. Usually they have to clear before changing rom.
– Wipe battery stats: Clears battery data, only required if the developer of the ROM requires it or if you want to fix bugs or calibrate the battery. If you do this option, It required to charge mobile 100% just after making it.
– Fix permissions: If you notice unexpected application closures, after you have installed the new rom, come back here and run it.
So, what, We need or we must do to make a Full Wipe or completely deleted?
wipe data/factory reset, format system, format cache y data y wipe dalvik cache.
Not all roms require a full erase, but if we do not mind losing all data on installed applications to start from scratch, It should ever do so.