I tried to flash a new firmware via flashfire and it got stuck on installing super su line so I soft reset it and .... yep, it is effed now. Was stuck on samsung screen but it now goes into download mode, problem is when I flash another firmware via odin it fails and I get stuck on "samsung" screen instead. I really need some help to recover my phone to a working state
I suggest you to install TWRP and try to wipe system and then you install a Custom ROM. When your device is ok, try to access Download Mode and use Odin to install Stock ROM again. When I had this same problem I did this procedure to unbrick my device and everything worked out in the end.
AC&MM
Galaxy J7 Pro
Moto X Force
Galaxy Tab S3
I don't know how to install twrp, odin does not want to install anything