Anyone have experience of bringing a S6 back from the dead?

I installed some recovery software, which half rooted my phone. I began to get error messages so wanted to flash the stock rom.

I downloaded the stock FW for my phone and used ODIN to flash.

ODIN should take 10 mins but hung and left for an hour with no change. So had to unplug the phone, now it says that it needs recovery via Smart Switch, but I can't use Smart Switch because it says the phone is unsupported.

Any ideas?