Incase you need it
Does this answer your question? 
Amal
gen2
The gen2 magic Mifare chip has no back door command. All sectors are simply open for writing. The advantage of the gen2 magic chip is that even NFC capable smartphones can simply issue write commands for any sector, including sector 0. This means a smartphone app could be used change the ID of the chip along with all the data in the manufacturing block. In addition to this, readers looking for magic chips ultimately have no good way to really tell if the chip is a magic chip or not. The down side is that the real Mifare S50 1k chip’s operation is emulated completely and accurately. There is no back door, so if one or more sectors on the chip become protected by access bit changes, you need valid keys in order to make further changes. In addition to this, if you set access bits such that the sector becomes locked, there is no way to recover that sector… it will be locked forever.