galaxy s6 g920f wont boot

hi, i hope someone can help me here. I have a g920f that just sits on the samsung logo. prior to this not booting problem i did the hack for stopping the disabled by EE problem. That seemed to go ok. disabled by EE went away.

then the phone said it had an update so i allowed it and update went ahead, then bang. non booting phone.

I have tried a lot of different firmwares and non have fixed the problem. I have done factory resets cleared cache but nothing has worked. I can still get into download mode so i believe it can be fixed. but i just do not know what else to try. i even tried deleting the OS (custom recovery) and re installing it but again that didn’t work.
So i do not know what else to try.

any help would be greatfully appreciated