ELAN Fingerprint Reader Working on HP EliteBook X G2i (04f3:0ca8)

[meirdick]

Following on from #5191 — same story, different laptop. The HP EliteBook X G2i 14" ("Next Gen AI PC" line) has an Elan 04f3:0ca8 (ELAN:ARM-M4) reader that isn't in libfprint's elanmoc2 driver table yet.

Instead of binary-patching the installed .so (which needs re-patching after every libfprint update), I built the elanmoc2 branch from source with 0ca8 added to elanmoc2_id_table, packaged as a normal pacman package that provides/conflicts libfprint — so it survives pacman -Syu/omarchy update without any pacman hook needed.

Steps:

1. git clone https://gitlab.freedesktop.org/Depau/libfprint.git -b elanmoc2
2. Add {.vid = ELANMOC2_VEND_ID, .pid = 0x0ca8, .driver_data = ELANMOC2_ALL_DEV}, to libfprint/drivers/elanmoc2/elanmoc2.c's elanmoc2_id_table
3. Build with a PKGBUILD (based on the AUR libfprint-elanmoc2-git one, pointed at the local patched source) via makepkg
4. pacman -U the result (conflicts with/replaces stock libfprint)
5. pacman -S fprintd usbutils, then fprintd-enroll/fprintd-verify as usual

Confirmed working: device detected as "ELAN Match-on-Chip 2", enroll completes, verify matches. PAM wiring for sudo/polkit/lock screen is just the standard pam_fprintd.so setup omarchy setup security fingerprint would normally do — its own hardware-detection script just doesn't recognize this Elan product string yet, so the wizard itself needs to be skipped and the steps run manually.

I've also filed this device ID upstream with the elanmoc2 maintainer.

Happy to share the exact PKGBUILD if anyone else has this laptop.