Exclamation [Q] [Important] Flash stock rom on Lg L7 without kdz?

Hi xda community,

I must send my lg on warrancy because the micro usb connector is damaged.
I', currently on a custom rom stock based, and i need a method to flash the original firmware V20D (i'm italian) and relock bootloader without the use of pc. Can i flash maybe using some apps on phone or the recovery?
I need a big help guys :/