Emergency firmware recovery(Maybe Possible)

[RJ96]

For those whose phone didnot update successfully and now doesnot boot 

Download samsung smart  switch software on laptop or desktop Pc

https://www.samsung.com/in/support/smart-switch/

This is how the software will look

Now as i have m20 it shows m20 connected successfully.

[Exploringmaharashtra]

if handset going download screen.. u can keystring factory reset. thats also one more way to handset on.