Home Button and Speaker broken after battery and lightning replacement

Hi all,

Yesterday I replaced the battery in my iPhone SE (1st gen) along with the lightning connector assembly (including mic, headphone jack etc).

Since the replacement, my home button does not work, neither does the loudspeaker, and neither does the headphone jack. The mic works, as does the charging port.

I’ve seen on some other forums on here about gold prongs on the home button or lightning connector that are to do with the home button circuit, but for love nor money I cannot work out where these prongs are. There is one prong on the underside of the home button, on the left hand side next to where the ribbon cable attaches to the screen assembly. There are no other prongs either on the screen assembly/home button or on the lightning connector (either new or old). What am I missing here?

I’ve also tried to reseat the speaker but had no luck, which is a huge problem when I use my phone for an alarm in the morning! Using the iFixIt guide, it looks like I seated the lightning connector assembly and ribbon cable in the correct place and the speaker is making contact with the appropriate points, but neither the speaker or headphone are working which makes me wonder if there’s a problem with something else…

Any advice very much welcome!!

(PS. This is not the first time I’ve been in an iPhone to replace a battery or a screen. It is however my first attempt at changing the lightning assembly)