If anyone is facing bootloader, bootloop, or bricked phone issues during one UI 8 upgrade - regardless if it is user interrupted - resolve the issues easily.
Open Smart switch on PC, restart phone using volume down + power (10 seconds), connect phone to PC.
Use Emergency Recovery option from Smart switch.
It takes time - around 10 GB ROM to be downloaded.
Cheers.
Comment below if this resolved your issue. For other issues, do let me know.
