Slow iPhone 6
It was scary, especially trying to connect back all the cables, but in the end it worked!
One step I did not see covered in the videos or step-by-step instructions was shaping the battery connection band to fit down in between the battery and the battery socket connection on the logic board. The old one I removed had a nice crease and slid right down into the slot. I had to create a similar fold in the new one, which made me nervous. I had to put an "U" turn in it and was afraid that might damage something, but apparently it did not.