[Xiaomi Mi 5s ROMs, Kernels, Recoveries, & Other De] wolkenjaeger:
Deleting/renaming the sensor folder is probably overkill: I followed this guide as well - https://xdaforums.com/google-nexus-5/general/sensors-fix-nexus-5-t2704915

However, I am still not able to have the fingerprint reader working :-/ There is no error on the display, it just does not react. Anyway:, I fired up Android Studio, so I could check for errors via ADB. When trying to add a fingerprint, this happens within seconds:

07-07 11:26:03.704 2636-24547/? E/QFP: QfpIvvCommand::printEnrollDebugLiteData: error rxd cmd=0 ver=0; have ver=3
07-07 11:26:03.705 2628-3962/? D/QTIFingerprintHal: android::QfpHALCallback::GetValidAcquiredInfo: acquisition info: -2
07-07 11:26:03.705 2628-3962/? D/QTIFingerprintHal: android::QfpHALCallback::onStatus: Status: -2 1002
07-07 11:26:03.706 2628-3962/? D/QTIFingerprintHal: android::QfpHALCallback::GetValidAcquiredInfo: acquisition info: -2
07-07 11:26:03.706 2628-3962/? D/QTIFingerprintHal: android::QfpHALStatusFilter::is_status_filtered:
07-07 11:26:03.706 2628-3962/? D/QTIFingerprintHal: need to filter no finger status
07-07 11:26:03.782 5132-5182/? I/WCNSS_FILTER: ibs_wcnss_bt_device_sleep: TX Awake, Sending SLEEP_IND
07-07 11:26:03.783 5132-5182/? I/WCNSS_FILTER: ibs_msm_serial_clock_vote: vote UART CLK OFF using UART driver's ioctl()
07-07 11:26:03.783 5132-5182/? D/WCNSS_FILTER: wcnss_release_wakelock
07-07 11:26:03.783 5132-5182/? I/WCNSS_FILTER: vote=1,new_vote =0, old_tx_vote=1, old_rx_vote=0
07-07 11:26:03.912 2636-24547/? I/QFP: QfpThreadEnroll::execute: enroll result -2
07-07 11:26:03.912 2636-24547/? E/QFP: QfpIvvCommand::printEnrollDebugLiteData: error rxd cmd=0 ver=0; have ver=3
07-07 11:26:03.912 2628-2628/? D/QTIFingerprintHal: android::QfpHALCallback::GetValidAcquiredInfo: acquisition info: -2
07-07 11:26:03.913 2628-2628/? D/QTIFingerprintHal: android::QfpHALCallback::onStatus: Status: -2 1002
07-07 11:26:03.913 2628-2628/? D/QTIFingerprintHal: android::QfpHALCallback::GetValidAcquiredInfo: acquisition info: -2
07-07 11:26:03.913 2628-2628/? D/QTIFingerprintHal: android::QfpHALStatusFilter::is_status_filtered:
07-07 11:26:03.913 2628-2628/? D/QTIFingerprintHal: no finger reached threshold, so not filtered
07-07 11:26:03.913 2628-2628/? D/QTIFingerprintHal: ServiceWrapper::ServiceWrapperNotify: mState=1
07-07 11:26:03.913 2628-2628/? D/fingerprintd: onAcquired(1002)
07-07 11:26:04.121 2636-24547/? I/QFP: QfpThreadEnroll::execute: enroll result -2
07-07 11:26:04.122 2636-24547/? E/QFP: QfpIvvCommand::printEnrollDebugLiteData: error rxd cmd=0 ver=0; have ver=3
07-07 11:26:04.123 2628-3962/? D/QTIFingerprintHal: android::QfpHALCallback::GetValidAcquiredInfo: acquisition info: -2
07-07 11:26:04.123 2628-3962/? D/QTIFingerprintHal: android::QfpHALCallback::onStatus: Status: -2 1002
07-07 11:26:04.124 2628-3962/? D/QTIFingerprintHal: android::QfpHALCallback::GetValidAcquiredInfo: acquisition info: -2
07-07 11:26:04.124 2628-3962/? D/QTIFingerprintHal: android::QfpHALStatusFilter::is_status_filtered:
07-07 11:26:04.124 2628-3962/? D/QTIFingerprintHal: need to filter no finger status
07-07 11:26:04.335 2636-24547/? I/QFP: QfpThreadEnroll::execute: enroll result -2
07-07 11:26:04.335 2636-24547/? E/QFP: QfpIvvCommand::printEnrollDebugLiteData: error rxd cmd=0 ver=0; have ver=3
07-07 11:26:04.335 2628-2628/? D/QTIFingerprintHal: android::QfpHALCallback::GetValidAcquiredInfo: acquisition info: -2
07-07 11:26:04.335 2628-2628/? D/QTIFingerprintHal: android::QfpHALCallback::onStatus: Status: -2 1002
07-07 11:26:04.335 2628-2628/? D/QTIFingerprintHal: android::QfpHALCallback::GetValidAcquiredInfo: acquisition info: -2
07-07 11:26:04.335 2628-2628/? D/QTIFingerprintHal: android::QfpHALStatusFilter::is_status_filtered:
07-07 11:26:04.335 2628-2628/? D/QTIFingerprintHal: need to filter no finger status
07-07 11:26:04.543 2636-24547/? I/QFP: QfpThreadEnroll::execute: enroll result -2
07-07 11:26:04.544 2636-24547/? E/QFP: QfpIvvCommand::printEnrollDebugLiteData: error rxd cmd=0 ver=0; have ver=3
07-07 11:26:04.545 2628-3962/? D/QTIFingerprintHal: android::QfpHALCallback::GetValidAcquiredInfo: acquisition info: -2
07-07 11:26:04.545 2628-3962/? D/QTIFingerprintHal: android::QfpHALCallback::onStatus: Status: -2 1002
07-07 11:26:04.545 2628-3962/? D/QTIFingerprintHal: android::QfpHALCallback::GetValidAcquiredInfo: acquisition info: -2
07-07 11:26:04.545 2628-3962/? D/QTIFingerprintHal: android::QfpHALStatusFilter::is_status_filtered:
07-07 11:26:04.545 2628-3962/? D/QTIFingerprintHal: need to filter no finger status
07-07 11:26:04.755 2636-24547/? I/QFP: QfpThreadEnroll::execute: enroll result -2
07-07 11:26:04.755 2636-24547/? E/QFP: QfpIvvCommand::printEnrollDebugLiteData: error rxd cmd=0 ver=0; have ver=3
07-07 11:26:04.755 2628-2628/? D/QTIFingerprintHal: android::QfpHALCallback::GetValidAcquiredInfo: acquisition info: -2
07-07 11:26:04.756 2628-2628/? D/QTIFingerprintHal: android::QfpHALCallback::onStatus: Status: -2 1002
07-07 11:26:04.756 2628-2628/? D/QTIFingerprintHal: android::QfpHALCallback::GetValidAcquiredInfo: acquisition info: -2
07-07 11:26:04.756 2628-2628/? D/QTIFingerprintHal: android::QfpHALStatusFilter::is_status_filtered:
07-07 11:26:04.756 2628-2628/? D/QTIFingerprintHal: need to filter no finger status
07-07 11:26:04.968 2636-24547/? I/QFP: QfpThreadEnroll::execute: enroll result -2
07-07 11:26:04.969 2636-24547/? E/QFP: QfpIvvCommand::printEnrollDebugLiteData: error rxd cmd=0 ver=0; have ver=3
07-07 11:26:04.970 2628-3962/? D/QTIFingerprintHal: android::QfpHALCallback::GetValidAcquiredInfo: acquisition info: -2
07-07 11:26:04.970 2628-3962/? D/QTIFingerprintHal: android::QfpHALCallback::onStatus: Status: -2 1002
07-07 11:26:04.970 2628-3962/? D/QTIFingerprintHal: android::QfpHALCallback::GetValidAcquiredInfo: acquisition info: -2
07-07 11:26:04.971 2628-3962/? D/QTIFingerprintHal: android::QfpHALStatusFilter::is_status_filtered:
07-07 11:26:04.971 2628-3962/? D/QTIFingerprintHal: need to filter no finger status
07-07 11:26:05.179 2636-24547/? I/QFP: QfpThreadEnroll::execute: enroll result -2
07-07 11:26:05.180 2636-24547/? E/QFP: QfpIvvCommand::printEnrollDebugLiteData: error rxd cmd=0 ver=0; have ver=3
07-07 11:26:05.180 2628-2628/? D/QTIFingerprintHal: android::QfpHALCallback::GetValidAcquiredInfo: acquisition info: -2
07-07 11:26:05.181 2628-2628/? D/QTIFingerprintHal: android::QfpHALCallback::onStatus: Status: -2 1002
07-07 11:26:05.181 2628-2628/? D/QTIFingerprintHal: android::QfpHALCallback::GetValidAcquiredInfo: acquisition info: -2
07-07 11:26:05.181 2628-2628/? D/QTIFingerprintHal: android::QfpHALStatusFilter::is_status_filtered:
07-07 11:26:05.181 2628-2628/? D/QTIFingerprintHal: need to filter no finger status
07-07 11:26:05.391 2636-24547/? I/QFP: QfpThreadEnroll::execute: enroll result -2
07-07 11:26:05.392 2636-24547/? E/QFP: QfpIvvCommand::printEnrollDebugLiteData: error rxd cmd=0 ver=0; have ver=3
07-07 11:26:05.392 2628-3962/? D/QTIFingerprintHal: android::QfpHALCallback::GetValidAcquiredInfo: acquisition info: -2
07-07 11:26:05.393 2628-3962/? D/QTIFingerprintHal: android::QfpHALCallback::onStatus: Status: -2 1002
07-07 11:26:05.393 2628-3962/? D/QTIFingerprintHal: android::QfpHALCallback::GetValidAcquiredInfo: acquisition info: -2
07-07 11:26:05.393 2628-3962/? D/QTIFingerprintHal: android::QfpHALStatusFilter::is_status_filtered:
07-07 11:26:05.393 2628-3962/? D/QTIFingerprintHal: no finger reached threshold, so not filtered
07-07 11:26:05.393 2628-3962/? D/QTIFingerprintHal: ServiceWrapper::ServiceWrapperNotify: mState=1
07-07 11:26:05.393 2628-3962/? D/fingerprintd: onAcquired(1002)
07-07 11:26:05.606 2636-24547/? I/QFP: QfpThreadEnroll::execute: enroll result -2
07-07 11:26:05.606 2636-24547/? E/QFP: QfpIvvCommand::printEnrollDebugLiteData: error rxd cmd=0 ver=0; have ver=3
07-07 11:26:05.606 2628-2628/? D/QTIFingerprintHal: android::QfpHALCallback::GetValidAcquiredInfo: acquisition info: -2
07-07 11:26:05.606 2628-2628/? D/QTIFingerprintHal: android::QfpHALCallback::onStatus: Status: -2 1002
07-07 11:26:05.606 2628-2628/? D/QTIFingerprintHal: android::QfpHALCallback::GetValidAcquiredInfo: acquisition info: -2
07-07 11:26:05.606 2628-2628/? D/QTIFingerprintHal: android::QfpHALStatusFilter::is_status_filtered:
07-07 11:26:05.606 2628-2628/? D/QTIFingerprintHal: need to filter no finger status
07-07 11:26:05.801 3157-3933/system_process E/wifi: Ignoring invalid tx_level info in radio_stats
07-07 11:26:05.815 2636-24547/? I/QFP: QfpThreadEnroll::execute: enroll result -2
07-07 11:26:05.815 2636-24547/? E/QFP: QfpIvvCommand::printEnrollDebugLiteData: error rxd cmd=0 ver=0; have ver=3
07-07 11:26:05.816 2628-3962/? D/QTIFingerprintHal: android::QfpHALCallback::GetValidAcquiredInfo: acquisition info: -2
07-07 11:26:05.816 2628-3962/? D/QTIFingerprintHal: android::QfpHALCallback::onStatus: Status: -2 1002
07-07 11:26:05.816 2628-3962/? D/QTIFingerprintHal: android::QfpHALCallback::GetValidAcquiredInfo: acquisition info: -2
07-07 11:26:05.817 2628-3962/? D/QTIFingerprintHal: android::QfpHALStatusFilter::is_status_filtered:
07-07 11:26:05.817 2628-3962/? D/QTIFingerprintHal: need to filter no finger status
07-07 11:26:06.024 2636-24547/? I/QFP: QfpThreadEnroll::execute: enroll result -2

FYI: Whenever I lift the finger from the home button/sensor, it jumps 'home' immediately, irrelevant how long I keep it on the button.

My main question is: How can I reinitialize the Fingerprint sensor (HAL), so I can use the fingerprint sensor again.