The fingerprint sensor will not function because the Secure Enclave Processor (SEP) cannot be downgraded.
that results in significant functional trade-offs, such as a non-working Touch ID Downgrade Iphone 5s To Ios 7
If you do not have saved blobs for your specific iPhone 5s, a traditional "untethered" downgrade is currently impossible. However, there are advanced "tethered" methods and specific exploits like LeetDown that have changed the game for A7 devices. Method 1: Using LeetDown (macOS Only) The fingerprint sensor will not function because the
: You must have saved SHSH blobs for iOS 7 while it was still being signed by Apple. Downgrade Iphone 5s To Ios 7