THE DEFINITIVE ANSWER ON BATTERY APNs
I'm fairly new to iFixIt, but I have been repairing iPhones (in the UK) for nearly two years now, so I'm very experienced with hardware repairs. However, one thing that's always got me confused is the APN numbers for batteries, and the real headaches they cause!
It seems that every iPhone I see has a different APN printed on the battery, and in my experience, replacing it with a battery of a different APN causes it to either not power on properly, or cause "Error 29" when trying to restore. These issues are fairly well-documented on here, and I accept that it is indeed an issue, solved by replacing the battery with the SAME APN. Fair enough.
But, here's the thing, how do people "get away" with DIY battery replacements? SURELY it can't just be chance that when they order a replacement battery, it just happens to match up to the APN of the battery currently in their iPhone? Because if it doesn't - this causes many problems as described above! I must have seen no less than 7 or 8 different APNs for 3G and 3GS batteries, so how can people possibly survive a battery replacement when they don't know the APN of their battery, or don't even know about the "APN story" at all?
Today, I went to replace a battery in an iPhone 3G, which had APN 616-0366. I only had APN 616-0428 iPhone 3G batteries, so I thought I'd give it a go anyway. Lo and behold... it wouldn't boot up! It got stuck at the Apple logo, and then started fading really slowly and powering off - obviously this was caused by the different type of battery I had just installed. I took out the 0428 and put the 0366 back in, and it worked just fine again. This situation has happened many times before with different APNs.
So, I was wondering if anybody had some sort of list of all the different APNs that are available, and which model of iPhone they work in? Surely big iPhone repair companies don't have stock of every single APN - or do they? If they do, then how does the logic work with DIY replacement batteries from eBay and the like? Do individuals always face problems when the wrong APN battery for their iPhone gets delivered?
Any clarification would be GREATLY received!
All the best,
Is this a good question?