In the link below you can do the payment to buy the code for unlocking Bios or Hard-Drive password for your laptop Dell Latitude e5520 (En el...
Dell latitude e5520 10ELT15F001-A dovanh krug_15_uma_sch_a01_0216_mb_tpm Schematics
Dell Latitude e5520 EC 2 MB Main 4 MB bios