Limit on total number of fingerprints stored?

0xC0DED0D0

Just added another profile, the ninth (including Owner), on my Pixel 9a. Works as well as every other profile does – except when it comes to enrollment for fingerprint biometric ID.

New fingerprints won't register! I have the same biometric ID set up in every other profile, so I'm guessing there's a set limit on the total number of fingerprints stored in the secure element?

Is this documented somewhere? And is the limit the same over the entire Pixel 9/10 range, or unique to the 9a?

Or, have I instead encountered an unexpected failure/bug?

Besides obvious rebooting, I did try deleting the profile, then re-adding it, with the same result.

Also experimented with adding additional fingerprints to existing profiles, and sure enough – same error.

Removing a fingerprint, then re-enrolling, does work however.

Running latest 2026021201, BTW.

userofgos

0xC0DED0D0 took me a while to find this thread, but there's a limit described here: https://discuss.grapheneos.org/d/1993-cant-add-a-5th-fingerprint/45

MetropleX 5 Fingerprints is a hardcoded limit and has been that way since Pixel 6, there is a workaround if you wish to have more but this requires alternating fingers for each input on one slot.

This obviously can impact on consistency for unlocking etc though so YMMV.

userofgos

0xC0DED0D0 Just added another profile, the ninth (including Owner), on my Pixel 9a. Works as well as every other profile does – except when it comes to enrollment for fingerprint biometric ID.

New fingerprints won't register! I have the same biometric ID set up in every other profile, so I'm guessing there's a set limit on the total number of fingerprints stored in the secure element?

So you have 8 fingerprints setup, one for each User Profile, and the same finger is used for all of them?

0xC0DED0D0 Still unsure if this is a "real" limit, or an error.

Iirc it's an upstream error/bug. The thread I linked to was the only one I could find talking about limits. But last year or the year before I read a few threads that were talking about upstream bugs relating to not being able to store more fingerprints or sometimes along that line. I've tried to find those threads but was only able to find the one I linked.

0xC0DED0D0

userofgos there's a limit described here

Thanks, but that thread deals with a different issue – the limit of registered fingerprints per profile. The limit I seem to have hit is on the total number of fingerprints across profiles altogether.

Still unsure if this is a "real" limit, or an error. As GrapheneOS significantly raises the number of profiles that can be used on Android, it seems to me that other users would have hit this limit before, and that it would be mentioned in GrapheneOS documentation.

Yet, I've been unable to find anything here on the forum.

Vsratoslav 8 profiles? this is only for experiment, or you have a separate profile for every app? 🙃

Just pretending I'm Jason Bourne... 😎

Vsratoslav

8 profiles? this is only for experiment, or you have a separate profile for every app? 🙃

DeletedUser639

This is my 'low brow' reasoning.
The dedicated space used to store bio-metric ID is not inexhaustible, and after mapping a single digit nine times or nine differing digits once, the space has simply been filled.