I broke the battery contact on the bottom of the circuit board, but I put a random small piece of metal in its place and both earbuds are working great now

Unplugging the ZIF connector isn't necessary, but it's nice to have the extra space on the first try; I skipped it on the second bud once I was more comfortable with it

I personally used E6000 glue and held the earbud in a clamp overnight until it set