Default Can bricked phone be fixed by replacing NAND chip?

Just a hypothetical question because I have been fortunate enough to have never hard bricked my phone. I've just been wondering if one could either access the chip through JTAG and reset it, or replace the chip entirely. Then, if that were possible, then could I go back to an unlocked bootloader too?

I know it's a BGA chip so I would need a reflow oven but I do electronics repair and I'm getting one soon anyway.