[Q] how to upgrade to kitkat without sdcard or online update topic

Hi
My friend's P6 sdcard slut is broken and therefore his phone doesnt support sdcard at mean time
He tried to get online upgrade via his phone but there were no updates for him
I want to know is there any way to use flash memory storage via OTG cable instead of Sdcard?
I tried to put dload folder in flash memory and go to bootloader but it didnt check external storage and only checked sdcard, also I tried TWRP bootloader but it also didnt recognize flash memory as storage to load zip file!!