The thing that you may not know is that third-party USB cables chargers can lead to bad results, but obviously you can’t stop everyone from using them. (Sometimes a third-party cable is the only one you’ve got access to, right?) Unfortunately, those third-party cables may actually be doing more damage than once originally considered.
According to mendmyi, which has been replacing batteries in previously dead-and-won’t-turn-back-on iPhones 5′s, the reason they’re not coming back on after being completely depleted is the third-party, cheaper cables, which are apparently damaging an internal component within the device. Indeed, mendmyi was seeing devices they had fixed plagued with the same issue, even after a battery replacement.
From mendmyi:
“Charging your iPhone using a third party charger or USB lead that does not regulate this as much allows for larger variables in voltage and current, this then damages the U2 IC and can leave you with a seemingly dead iPhone 5. Another common reason for this is also charging your iPhone 5 from the cigarette lighter of your car. This does not regulate the voltage as well as the original AC adapter as the power is coming from the alternator. If you need to charge our iPhone or any electrical equipment in your car we would recommend a good quality inverter with your original charger and USB lead.â€
After some investigating, mendmyi was able to narrow down the issue, and found that it’s centered around a part called the U2 IC chip. This particular piece controls quite a bit, including the charge to the battery, the sleep/wake button, and regulates the charging to the power IC that ultimately charges the iPhone 5. The U2 IC is fitted to the logic board with 36 pins, and mendmyi says replacing that particular piece is quite involved.
