As I remember there is a BIOS that checks all the part numbers in the phone I'm not sure if you can buy apple parts but I would only use apple parts to fix BECAUSE I broke the home button flex ribbon cable on my I 6 plus and I got some aftermarket cable also a heat shield with cable and none worked wouldnt boot up at all so find orginal parts wouldnprobably solve your problem. As for mine I'm having to send it in on warranty with all my info still on phone . I hope its dead forever.
What would be really good is to have the circuit dia. for ipod touch 2-3gen. it would help to locate the jump points_ I have googled them but there not easy to find. I have pulled a pad off headphone jack and a trace next to battery attach points_If a person knew where to find the next jump point was, you could save them. As for buying 40-50 dollar epoxy is a bit steep if you only had 1 to fix and even spending 30 dollars on silver paint is still a bit steep when you price what ipod touch 2-3 gens. go for, but it would still teach you HOW TO, just need to find a less expensive supplier of the products ( maybe EBAY ) but this post is great info for those wanting to fix instead of throwing away there ipod iphone.. I give this a +10