We been repaired many home button with Touch ID for older models. But none of those are cracked on surface. Most of them are ribbon flex broken, or either water damaged which still success repaired.
If your case is like photo at below...
|iPhone 8 Home button cracked|
|If unable to record new finger print, then you are unlucky. The sensor surface is completely damaged and now so far there is no way to repair it. (Apr 2018)|
- Touch ID surface cracked - Can record new finger print - Can repair.
- Touch ID surface cracked - unable to record finger print - Can't repair
- Touch ID flex broken - Can repair as long you keep the original
- Home button not working and Touch ID works - Can repair
- Home button works and Touch ID not - Can repair if it's original button.