My Problem
My iphone4s' battery has gone bad a while ago so I swapped it with a third party battery. The phone was originally on ios7 and I've decided recently to upgrade it to ios9. However iTunes would give error code 29 during upgrade (and restore after original error rendered my phone is DFU mode) which I suspected that it was caused by a battery that failed to respond or pass apple's check. So I ordered an iFixit battery in hope that it'd work.
My Fix
The repair was literally a 30 second job: pop the case, put the new battery in then restore.
My Advice
Do not buy parts from unknown parties cause their parts may not pass Apple's notorious hardware check during restoring or upgrading.
One Comment
Worth mentioning that this phone was sitting in my drawer collecting dust for a couple of months because of this cheap battery.
HANNAN AI - Reply