From real-world tests (2017–2018):
You should never download modem files from random file-hosting sites (like Mediafire or Mega) linked in YouTube descriptions, as they may contain modified binaries.
The Safe Method (SamFw / SamMobile):
If you stubbornly tried to flash a modern U6 modem file (meant for an S20) onto an old G925F, here is what happens:
Many users chase the "U6" file because they think a higher number means better signal. This is false. Modem firmware is tied to bootloader versions. g925f modem file u6
If you have a G925F (Galaxy S6 Edge) , the final bootloader version is U6 from 2018. The latest modem file for that phone is CP_G925FXXU6ESF1. That is the only "U6 modem file" that exists for that model.
If you have a G985F (Galaxy S20+) , the U6 modem is current as of mid-2023. From real-world tests (2017–2018):
Users typically flash standalone modem files for specific reasons:
Note: These are generic instructions; exact steps vary by firmware source and tools. Assume Odin flashing on a Windows PC for Samsung devices. You should never download modem files from random