Many iPhone users have been stuck with iPhone restore error 53 and ended up with bricked phone when they had iPhone 6 home button broken. So they were forced to shell out $300+ at Apple Store to get refurbished phone if the phone was out of warranty.
Finally it seems Apple has released a software update that allows customers who have encountered this error message to successfully restore their device using iTunes on a Mac or PC.
So if you have bricked iPhone with error 53, we suggest you to try connecting to iTunes and restore the phone again starting today Feb 18th, 2016.