g903f S5 Flash Problem Help (1 Viewer)

Where are specialist for Samsung?

Following problem!
G903F (bootloop Problem)
try to flash -> after flash show dm verification failed!!
try a few 4 parts stock firmware -> still not boot only samsung logo then hang with blue led flash.
in donwload mode it shows sytem custom, but only used stock firmware.

Twrp not work because blocked by frp
How can i find out right firmware and which region this phone is

its u2
but i dont know which firmware was originally first on phone