[BUG]: Elan Fingerprint Reader 04f3:0c00 not detected on Ubuntu 24.04

[gandinistefano7-netizen]

1. Bug Description
   My Elan fingerprint reader with USB ID 04f3:0c00 is not being detected by the python-validity driver. The installation seems to complete, but the service fails to start because it cannot find a supported device. Commands like fprintd-enroll and validity-sensors-firmware both fail.

2. System Details
   • Fingerprint Reader: Elan Microelectronics Corp. ELAN:ARM-M4
   • USB ID: 04f3:0c00
   • Operating System: Ubuntu 24.04 LTS "Noble Numbat"
   • Driver Source: PPA ppa:uunicorn/open-fprintd
   • Installed Packages:
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   rc fprintd 1.94.2-2 amd64 D-Bus daemon for fingerprint reader access
   ii fprintd-clients 1.90.1-1ubuntu5 amd64 PAM module for fingerprint authentication through fprintd
   ii open-fprintd 0.7ppa2 all Open fprintd DBus service.
   ii python3-validity 0.15ppa2 all Validity Fingerprint Sensor DBus Driver

   • Kernel Version:
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   Linux ubuntu-desktop 6.8.0-85-generic Add pod2man as a dependency #85-Ubuntu SMP PREEMPT_DYNAMIC Thu Sep 18 15:26:59 UTC 2025 x86_64 x86_64 x86_64 GNU/Linux

3. Steps to Reproduce

   1. Add the ppa:uunicorn/open-fprintd repository.
   2. Run sudo apt update and sudo apt install open-fprintd fprintd-clients python3-validity.
   3. The installation of python3-validity fails during the post-installation script with the error: Exception: No supported validity device found.
   4. Any attempt to enroll a fingerprint fails with list_devices failed:.

4. Diagnostic Logs
   Service Status Log:
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   ott 15 18:06:24 ubuntu-desktop systemd[1]: Started python3-validity.s>
   ott 15 18:06:27 ubuntu-desktop dbus-service[1443]: Traceback (most re>
   ott 15 18:06:27 ubuntu-desktop dbus-service[1443]: File "/usr/lib/p>
   ott 15 18:06:27 ubuntu-desktop dbus-service[1443]: main()
   ott 15 18:06:27 ubuntu-desktop dbus-service[1443]: File "/usr/lib/p>
   ott 15 18:06:27 ubuntu-desktop dbus-service[1443]: init.open()
   ott 15 18:06:27 ubuntu-desktop dbus-service[1443]: File "/usr/lib/p>
   ott 15 18:06:27 ubuntu-desktop dbus-service[1443]: usb.open()
   ott 15 18:06:27 ubuntu-desktop dbus-service[1443]: File "/usr/lib/p>
   ott 15 18:06:27 ubuntu-desktop dbus-service[1443]: self.open_dev(>
   ott 15 18:06:27 ubuntu-desktop dbus-service[1443]: File "/usr/lib/p>
   ott 15 18:06:27 ubuntu-desktop dbus-service[1443]: raise Exceptio>
   ott 15 18:06:27 ubuntu-desktop dbus-service[1443]: Exception: No matc>
   ott 15 18:06:27 ubuntu-desktop systemd[1]: python3-validity.service: >
   ott 15 18:06:27 ubuntu-desktop systemd[1]: python3-validity.service: >
   ott 15 18:06:27 ubuntu-desktop systemd[1]: python3-validity.service: >
   ott 15 18:12:38 ubuntu-desktop systemd[1]: Started python3-validity.s>
   ott 15 18:12:40 ubuntu-desktop dbus-service[6227]: Traceback (most re>
   ott 15 18:12:40 ubuntu-desktop dbus-service[6227]: File "/usr/lib/p>
   ott 15 18:12:40 ubuntu-desktop dbus-service[6227]: main()
   ott 15 18:12:40 ubuntu-desktop dbus-service[6227]: File "/usr/lib/p>
   ott 15 18:12:40 ubuntu-desktop dbus-service[6227]: init.open()
   ott 15 18:12:40 ubuntu-desktop dbus-service[6227]: File "/usr/lib/p>
   ott 15 18:12:40 ubuntu-desktop dbus-service[6227]: usb.open()
   ott 15 18:12:40 ubuntu-desktop dbus-service[6227]: File "/usr/lib/p>
   ott 15 18:12:40 ubuntu-desktop dbus-service[6227]: self.open_dev(>
   ott 15 18:12:40 ubuntu-desktop dbus-service[6227]: File "/usr/lib/p>
   ott 15 18:12:40 ubuntu-desktop dbus-service[6227]: raise Exceptio>
   ott 15 18:12:40 ubuntu-desktop dbus-service[6227]: Exception: No matc>
   ott 15 18:12:40 ubuntu-desktop systemd[1]: python3-validity.service: >
   ott 15 18:12:40 ubuntu-desktop systemd[1]: python3-validity.service: >
   ott 15 18:12:40 ubuntu-desktop systemd[1]: python3-validity.service: >

Verbose USB Device Information:
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Bus 003 Device 003: ID 04f3:0c00 Elan Microelectronics Corp. ELAN:ARM-M4
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 2.00
bDeviceClass 0 [unknown]
bDeviceSubClass 0 [unknown]
bDeviceProtocol 0
bMaxPacketSize0 8
idVendor 0x04f3 Elan Microelectronics Corp.
idProduct 0x0c00 ELAN:ARM-M4
bcdDevice 2.83
iManufacturer 1 ELAN
iProduct 2 ELAN:ARM-M4
iSerial 0
bNumConfigurations 1
Configuration Descriptor:
bLength 9
bDescriptorType 2
wTotalLength 0x0053
bNumInterfaces 1
bConfigurationValue 1
iConfiguration 0
bmAttributes 0xa0
(Bus Powered)
Remote Wakeup
MaxPower 100mA
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 0
bAlternateSetting 0
bNumEndpoints 8
bInterfaceClass 255 Vendor Specific Class
bInterfaceSubClass 0 [unknown]
bInterfaceProtocol 0
iInterface 0
** UNRECOGNIZED: 09 21 10 01 00 01 22 15 00
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x81 EP 1 IN
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0040 1x 64 bytes
bInterval 1
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x01 EP 1 OUT
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0040 1x 64 bytes
bInterval 1
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x82 EP 2 IN
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0040 1x 64 bytes
bInterval 1
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x02 EP 2 OUT
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0040 1x 64 bytes
bInterval 1
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x83 EP 3 IN
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0040 1x 64 bytes
bInterval 1
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x03 EP 3 OUT
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0040 1x 64 bytes
bInterval 1
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x84 EP 4 IN
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0040 1x 64 bytes
bInterval 1
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x04 EP 4 OUT
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0040 1x 64 bytes
bInterval 1
Device Status: 0x0000
(Bus Powered)

5. Additional Information
   The issue persists after a full system reboot. A custom udev rule was also tested to ensure correct permissions, but it did not solve the problem. Further logs can be provided if required. Thank you for your work on this project.