How do I choose the correct firmware for my phone? I have a Samsung a310f that is frp locked on the back IT'S written yately "gugg", UK which could mean that it was made in the UK or for the UK now when I am on SamMobile I don't know if choosing the one for my country or the one that made the phone.
For this model you can flash many official ROM versions.
https://fw.updato.com was a good source of download collection and tutorials in early years, but this site became worst since they monetarized everything
Be aware there is downgrade protection for bootloader and flashing another ROM does not remove FRP lock. Only the methods for by-pass FRP may vary.
For Android 7 Nougat CF-Auto-Root is available but it requires OEM unlocking in developer options
Flashing TWRP is another option but it requires OEM unlocking, too