Most phones are full disk encrypted. So they don't need to zero out the whole disk... They just need to zero out the part of the disk that stores the encryption key. Once the encryption key is erased, the rest of the disk is essentially random noise.
Most phones are full disk encrypted. So they don't need to zero out the whole disk... They just need to zero out the part of the disk that stores the encryption key. Once the encryption key is erased, the rest of the disk is essentially random noise.