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[GUIDE] Fix Fingerprint Scanner with "corrupt" persist in 15 minutes!

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starcms

Senior Member
Omg, I've been messing with this thing for 2 months trying to fix it, all because I didn't take a backup of my /persist as soon as I got the phone, but there is a way to fix it!!! The only pre-requisites are that:
A) you still have your own /persist (that came with your specific phone, didn't overwrite it with one from the forums and didn't save your original somewhere) AND
B) all sensors still work (only the fingerprint scanner is broken) AND
C) that you have NEVER ran the hidden fingerprint calibration tools accessible from *#808# (unless you have a backup of /persist from before you did that)

Follow these simple instructions and enjoy:

https://forum.xda-developers.com/oneplus-8/how-to/guide-fix-persist-img-loss-finger-print-t4126455

You can ignore the entire part about having to run the MSM tool to roll back to a previous version of OOS (Step 2). Therefore, no data is lost, no factory reset is required, etc.

Also in very first part of Step 4, you need to dial *#808#, not *#801#

It took me less than 15 minutes and now it's good as new!!! Please give the OP thanks! He spent almost 200 hours figuring this out (and I don't doubt it; I must have spent easily over 20 hours myself and didn't get anywhere...). All I did was find his genius instructions and post them here.

Edit: And to add one last step to the guide, after you finish and get the fp scanner working again, please be sure to take a backup of your now fixed persist partition and store it in at least two different locations. Because if you are reading this, you are most likely modding your phone with at least Magisk (why else unlock the bootloader? ;) and almost anything can cause persist to be corrupted. For me, it was simply installing a bad build of magisk canary back in May that did it. It's not just important for those installing aftermarket ROMs. It's vital for anyone who even thinks about unlocking the bootloader on this device. Because even the act of relocking the bootloader has caused persist to be corrupted for some...

Edit2: If you run the MSM tool after fixing persist, or manually relock the bootloader, you'll wind up with your FP being broken again. I'm assuming because the checksum of the "fixed" persist doesn't match that of the original, unmodified persist, so it gets marked as corrupt again. So you'll need to unlock the bootloader and restore/flash your backed up, fixed persist (you did back it up this time, right? ;) Impossible to run msm tool to get back to stock AND have FP working. Bootloader must be unlocked after using msm tool and fixed persist restored.
 
Last edited:
please help HD9010 indian firmware currently..before i had global

i messed up my persist too while reverting back from open beta to stable via fastboot
now fingerprint enrollment error
i tried the guide but its not the same with 7tpro

there wasnt 'gf_persist.so' in data folder of my extracted persist.img
and calibrating was confusing for me but i did it upro my limit but i didnt have those many reds as the original OP had in his guide video while calibrating the fp
so please can you be kind enough to share your whole process that you used to manage the fingerprint error issue?
like what roms you used before and after or during fix?

and lastly, since the backedup persist didnt work i deleted and again backedup the persist in next attempt so it means my fingerprint is gone permanently? maybe?

please help me..ive spent my whole night and day searching and trying workarounds flashing roms back and forth
 
Last edited:

starcms

Senior Member
i messed up my persist too while reverting back from open beta to stable via fastboot
now fingerprint enrollment error
i tried the guide but its not the same with 7tpro

there wasnt 'gf_persist.so' in data folder of my extracted persist.img
and calibrating was confusing for me but i did it upro my limit but i didnt have those many reds as the original OP had in his guide video while calibrating the fp
so please can you be kind enough to share your whole process that you used to manage the fingerprint error issue?
like what roms you used before and after or during fix?

and lastly, since the backedup persist didnt work i deleted and again backedup the persist in next attempt so it means my fingerprint is gone permanently? maybe?

please help me..ive spent my whole night and day searching and trying workarounds flashing roms back and forth

I used his exact instructions on my 7T Pro 5G McLaren edition from T-Mobile. With a few helpful tips I added. You must have the global version of the 7T Pro McLaren since you are talking about open beta and stable releases. Unfortunately I can't help you there. It seems that the TMobile 7T Pro 5G McLaren is much more similar to the OP8 in some ways than the global 7T Pro, especially when it comes to OOS, partitioning, extra security crap, etc.

Edit:. You are in the wrong forum. You don't even have the global 7T Pro McLaren. You have the HD1910 Global (originally Chinese version) 7T Pro. Wrong forum. The 7T Pros didn't even have this issue (or if they did, it was no where near as widespread, I've never even seen it mentioned a single time). To the best of my knowledge, it began with the 7T Pro 5G McLaren from T-Mobile which was the newest phone released by 1+ until the OP8.

And if you deleted your backup of your original persist after trying to fix it unsuccessfully, it's now broken forever regardless. You need to RMA.
 
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starcms

Senior Member
Late response, but this worked 100% for me after switching back to stock from AOSiP.

Thank you!

Glad to hear it worked!


One important thing to add:

If you run the MSM tool after fixing persist, or manually relock the bootloader, you'll wind up with your FP being broken again. I'm assuming because the checksum of the "fixed" persist doesn't match that of the original, unmodified persist, so it gets marked as corrupt again. So you'll need to unlock the bootloader and restore/flash your backed up, fixed persist (you did back it up, right? ;). Impossible to run msm tool to get back to stock AND have FP working. Bootloader must be unlocked after using msm tool and fixed persist restored.
 
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cgrimm9

Senior Member
Sep 4, 2010
243
52
Glad to hear it worked!


One important thing to add:

If you run the MSM tool after fixing persist, or manually relock the bootloader, you'll wind up with your FP being broken again. I'm assuming because the checksum of the "fixed" persist doesn't match that of the original, unmodified persist, so it gets marked as corrupt again. So you'll need to unlock the bootloader and restore/flash your backed up, fixed persist (you did back it up, right? ;). Impossible to run msm tool to get back to stock AND have FP working. Bootloader must be unlocked after using msm tool and fixed persist restored.

in the guide it tells you to get your phone into factory mode but does not tell you to take it out of factory mode. of you turn factory mode off and use the msm tool will fingerprint still work afterwords
 

cgrimm9

Senior Member
Sep 4, 2010
243
52
I did step three says.
3. Next step is to unlock the built in 'Factory Mode' I have a guide on how to do this below.
https://forum.xda-developers.com/oneplus-8-pro/how-to/guide-unlock-factory-mode-root-t4118527

No where on this instructions says to relock the factory mode. I am just asking if you where to do that will fingerprint scanner work after doing msm tool.

I did the process 2 times now. Have no interest in doing it again unless I need to update. I just putting some thought in why I don't know if it's relavent or not just asking. sometimes a difficult problem can have a easy solution just got to figure it out
 

starcms

Senior Member
I did step three says.
3. Next step is to unlock the built in 'Factory Mode' I have a guide on how to do this below.
https://forum.xda-developers.com/oneplus-8-pro/how-to/guide-unlock-factory-mode-root-t4118527

No where on this instructions says to relock the factory mode. I am just asking if you where to do that will fingerprint scanner work after doing msm tool.

I did the process 2 times now. Have no interest in doing it again unless I need to update. I just putting some thought in why I don't know if it's relavent or not just asking. sometimes a difficult problem can have a easy solution just got to figure it out

Yes, you can relock factory mode when done. Just re-edit those 2 lines. And once you have your FP working again, please be sure to make a backup of your fixed persist.img. Then you'll never have to do all the steps again. Simply restore your fixed persist.img if FP ever breaks again.
 
Last edited:

albinoman887

Inactive Recognized Developer
Dec 14, 2010
3,899
16,161
Snohomish, WA
Omg, I've been messing with this thing for 2 months trying to fix it, all because I didn't take a backup of my /persist as soon as I got the phone, but there is a way to fix it!!! The only pre-requisites are that:
A) you still have your own /persist (that came with your specific phone, didn't overwrite it with one from the forums and didn't save your original somewhere) AND
B) all sensors still work (only the fingerprint scanner is broken) AND
C) that you have NEVER ran the hidden fingerprint calibration tools accessible from *#808# (unless you have a backup of /persist from before you did that)

Follow these simple instructions and enjoy:

https://forum.xda-developers.com/oneplus-8/how-to/guide-fix-persist-img-loss-finger-print-t4126455

You can ignore the entire part about having to run the MSM tool to roll back to a previous version of OOS (Step 2). Therefore, no data is lost, no factory reset is required, etc.

Also in very first part of Step 4, you need to dial *#808#, not *#801#

It took me less than 15 minutes and now it's good as new!!! Please give the OP thanks! He spent almost 200 hours figuring this out (and I don't doubt it; I must have spent easily over 20 hours myself and didn't get anywhere...). All I did was find his genius instructions and post them here.

Edit: And to add one last step to the guide, after you finish and get the fp scanner working again, please be sure to take a backup of your now fixed persist partition and store it in at least two different locations. Because if you are reading this, you are most likely modding your phone with at least Magisk (why else unlock the bootloader? ;) and almost anything can cause persist to be corrupted. For me, it was simply installing a bad build of magisk canary back in May that did it. It's not just important for those installing aftermarket ROMs. It's vital for anyone who even thinks about unlocking the bootloader on this device. Because even the act of relocking the bootloader has caused persist to be corrupted for some...

Edit2: If you run the MSM tool after fixing persist, or manually relock the bootloader, you'll wind up with your FP being broken again. I'm assuming because the checksum of the "fixed" persist doesn't match that of the original, unmodified persist, so it gets marked as corrupt again. So you'll need to unlock the bootloader and restore/flash your backed up, fixed persist (you did back it up this time, right? ;) Impossible to run msm tool to get back to stock AND have FP working. Bootloader must be unlocked after using msm tool and fixed persist restored.

yep. same here spent so much time on it. Then me and that dev crossed paths. i told him what i found and he told me what he found and together it birthed that hack

fp also works in custom roms now
 

Trevaryn

Senior Member
Jun 23, 2011
54
24
Washington
OnePlus 9 Pro
So this fixed my issue with registering my fingerprints, but even after registering 5 prints, when I go to unlock my phone or anything that uses my prints scanning fails like 90% of the time. I have to press really hard or just put in my pin to get my phone to unlock. I removed my screen protector and cleaned my screen. Is there a way to recalibrate the scanner?
 

starcms

Senior Member
So this fixed my issue with registering my fingerprints, but even after registering 5 prints, when I go to unlock my phone or anything that uses my prints scanning fails like 90% of the time. I have to press really hard or just put in my pin to get my phone to unlock. I removed my screen protector and cleaned my screen. Is there a way to recalibrate the scanner?

Program each finger twice. Also, it'll get much, much, much better with time as it autocalibrates/learns over a week or so.
 

starcms

Senior Member
I don't quite follow step 5 in the guide:



Also, do you run the steps after flashing a custom ROM?

For step 5, just extract it as if it was a zip file on your PC.

After fixing persist and getting FP working, make sure you make a backup of the fixed persist.img and save it in at least 2 or 3 different places to be safe. Occasionally for custom ROMs, to get the FP working after flashing ROM, take your fixed persist, go to fastboot, and do "fastboot flash persist your_backed_up_fixed_persist.img"
 
i just wanted to say that for some weird or maybe lucky reason, i did not have to reflash my backed up persist after using the msm to get back to stock from the aosip custom rom. I used the bootloader unlock trick through modded msm to install the rom and i went back using msm and fingerprint worked on the get go. I did not have to unlock bootloader and reflash persist.img .. not sure why i didnt have to its weird ( i never flashed my persist at all, even after installing the custom rom)
 

mrshahriar

Member
Aug 30, 2020
7
1
please help HD9010 indian firmware currently..before i had global

i messed up my persist too while reverting back from open beta to stable via fastboot
now fingerprint enrollment error
i tried the guide but its not the same with 7tpro

there wasnt 'gf_persist.so' in data folder of my extracted persist.img
and calibrating was confusing for me but i did it upro my limit but i didnt have those many reds as the original OP had in his guide video while calibrating the fp
so please can you be kind enough to share your whole process that you used to manage the fingerprint error issue?
like what roms you used before and after or during fix?

and lastly, since the backedup persist didnt work i deleted and again backedup the persist in next attempt so it means my fingerprint is gone permanently? maybe?

please help me..ive spent my whole night and day searching and trying workarounds flashing roms back and forth
Brother i am suffering the same problem with same device OP 7T PRO, Did you managed to solve the problem? It will be a great help if you tell me
My mail id - [email protected]
 

starcms

Senior Member
please help HD9010 indian firmware currently..before i had global

i messed up my persist too while reverting back from open beta to stable via fastboot
now fingerprint enrollment error
i tried the guide but its not the same with 7tpro

there wasnt 'gf_persist.so' in data folder of my extracted persist.img
and calibrating was confusing for me but i did it upro my limit but i didnt have those many reds as the original OP had in his guide video while calibrating the fp
so please can you be kind enough to share your whole process that you used to manage the fingerprint error issue?
like what roms you used before and after or during fix?

and lastly, since the backedup persist didnt work i deleted and again backedup the persist in next attempt so it means my fingerprint is gone permanently? maybe?

please help me..ive spent my whole night and day searching and trying workarounds flashing roms back and forth

The instructions only work for the T-Mobile 7T Pro 5G Mclaren edition, all OP8, all OP8 pro, no idea about OP8T. That's because this was the first device that OnePlus used a different format for persist. That's confirmed by you not having gf_persist.so.

You would need to look at the forums for the OnePlus 7T Pro for a possible answer: https://forum.xda-developers.com/c/oneplus-7t-pro.9327/ The forums you are in now are ONLY for the HD1925, the T-Mobile branded 7T Pro 5G Mclaren variant.


And lastly, if you deleted your original persist.img (the one with broken fp), which it sounds like you did, and then wiped persist again afterwards, then there is absolutely no hope of fixing it besides sending it to OnePlus. Because you've lost your entire original persist if that is the case, unless you still have a backup of original persist.img with broken fp from before you tried fixing it.
 

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  • 1
    As you probably found out by now, the FP scanner stopped working like new. It seems to only work like new after first following the steps posted. After a reboot or two, autoCalibrationParams.so gets updated (as it should) but it makes the FP scanner only work a small percentage of the time/works like crap. I've pretty much given up trying to fully understand why it does this and there is no permanent fix (besides sending it to 1+ for a fingerprint recalibration or motherboard replacement)
    That's not in my case, because after copying the files as i mentioned in above post, i restarted many times after installing swift installer and dark mode using it. And my fingerprint is working flawless uptill now. All my base cal dates are of 2019 in data and eng mode folder.

    What worked for me was copying all files from original non broken persist to my device in data and eng mode folder.

    Edit: checked again and found all files in data folder have dates back of 2019, only autocalibrationparam.so has date of 22sep2021.
  • 5
    Omg, I've been messing with this thing for 2 months trying to fix it, all because I didn't take a backup of my /persist as soon as I got the phone, but there is a way to fix it!!! The only pre-requisites are that:
    A) you still have your own /persist (that came with your specific phone, didn't overwrite it with one from the forums and didn't save your original somewhere) AND
    B) all sensors still work (only the fingerprint scanner is broken) AND
    C) that you have NEVER ran the hidden fingerprint calibration tools accessible from *#808# (unless you have a backup of /persist from before you did that)

    Follow these simple instructions and enjoy:

    https://forum.xda-developers.com/oneplus-8/how-to/guide-fix-persist-img-loss-finger-print-t4126455

    You can ignore the entire part about having to run the MSM tool to roll back to a previous version of OOS (Step 2). Therefore, no data is lost, no factory reset is required, etc.

    Also in very first part of Step 4, you need to dial *#808#, not *#801#

    It took me less than 15 minutes and now it's good as new!!! Please give the OP thanks! He spent almost 200 hours figuring this out (and I don't doubt it; I must have spent easily over 20 hours myself and didn't get anywhere...). All I did was find his genius instructions and post them here.

    Edit: And to add one last step to the guide, after you finish and get the fp scanner working again, please be sure to take a backup of your now fixed persist partition and store it in at least two different locations. Because if you are reading this, you are most likely modding your phone with at least Magisk (why else unlock the bootloader? ;) and almost anything can cause persist to be corrupted. For me, it was simply installing a bad build of magisk canary back in May that did it. It's not just important for those installing aftermarket ROMs. It's vital for anyone who even thinks about unlocking the bootloader on this device. Because even the act of relocking the bootloader has caused persist to be corrupted for some...

    Edit2: If you run the MSM tool after fixing persist, or manually relock the bootloader, you'll wind up with your FP being broken again. I'm assuming because the checksum of the "fixed" persist doesn't match that of the original, unmodified persist, so it gets marked as corrupt again. So you'll need to unlock the bootloader and restore/flash your backed up, fixed persist (you did back it up this time, right? ;) Impossible to run msm tool to get back to stock AND have FP working. Bootloader must be unlocked after using msm tool and fixed persist restored.
    1
    Hi All respected seniors!

    can anybody please explain procedure for original persist.img backup. I have a TMO 7T PRO Mclaren and after bootloader unlock at android 11 after magisk i took all partition backup including then working finger print persist.img but after installing several magisk mods one day i woke up with no fingerpring hardware error. now i have my original persist.img at hand. i also backed up this corrupt fp persist.img.

    every one here has workaround for broken persist.img but i want to know the restoration method of original woking persist.img backed up before any sensor issues..

    please help!

    I already answered in your other thread. Please don't double post.
    1
    Okay.

    But I'm thinking of another option, as i backed up my original non broken persist.img after unlocking bootloader via MSM tool, so im sure that partition backup would have original non corrupt unlock.so file in it. Along with original persist.so

    So the question, can that file be used in any way to help this issue.

    Need your precious expert opinion in this regard..

    Also should i continue replying in this thread or move the discussion to HD1925's.

    If gf_persist.so is what's causing the issue of it not working anywhere near as well as it should, then you/we are crap outta luck because that file must be over-written as per the instructions to get the FP sensor working again. Only way to properly restore that file is per re-cal by OnePlus. However, at least on the OP8, this file only seems to "tell" the system whether or not the FP cal data is "valid" and doesn't contain any actual calibration parameters.

    Our HD1925 is slightly different however because the OP8 doesn't even have a gf_persist_unlock.so file. However, your idea is an excellent one. The file dates on your pre-corrupted, backed-up persist partition in /persist/data should all share the same exact date (except for autoCalibrationParams.so_0) -- the date being when the phone was originally built and calibrated by OnePlus. Most likely a date in late 2019.

    If the file date of gf_persist_unlock.so (or any other files in that directory besides gf_persist.so and autoCalibrationParams.so_0) in your backed-up, pre-corrupt persist is still showing back in late 2019, but the persist version you are currently using shows much more recent dates for any of these files (again, excluding gf_persist.so and autoCalibrationParams.so_0), specifically gf_persist_unlock.so, then do what you just thought of -- restore the original, "non-corrupted cal data but apparently corrupt gf_persist.so" version of persist, get a copy of /persist/data/gf_persist_unlock.so, then restore the "fixed" version of persist and copy over gf_persist_unlock.so.

    But this will only have a chance of working if the date of gf_persist_unlock.so matches everything else in that folder (again, excluding gf_persist.so and autoCalibrationParams.so_0) -- a date in late 2019 or possibly early 2020, meaning it has never been touched or modified in any way since the phone was originally made.
    1
    So i think we might have a chance.. im attaching my persist.img extraction. Give a look at dates.. i think i have original OP cal at hand.

    Yep, looks great. Just copy/overwrite the fixed gf_persist.so from following the instructions

    Edit: just so strange you are even having issue since gf_persist.so has never even been altered/corrupted judging by the file date.
    1
    Figured I would post this here for anyone that had my issue. The Fingerprint fix from the OP works perfect but after getting back the fingerprint it never registered my fingerprint properly(maybe 1 out of every 10 tries).

    I decided to rerun the calibration test.

    delete all fingerprints first if you can

    1) Start test nothing pressed just hit start
    2) Start flesh sleeve - quickly put your finger or palm completely over the white circle
    3) Black Rubber Sleeve Test - Hit start and I used a black rubber mat I have to cover the whole bottom of the screen
    4) Positioning Circle Test I quickly just used my thumb to cover the circles
    5) Stripe Rubber Sleeve Test I rubber mat to cover half the circle.

    Completed the file copy and rebooted

    Now it works 4 out of 5 times - I can now disable face scanner again yay. What I also noticed is it take a bit longer to process the fingerprint.

    Again thank you to the OP for this fix!

    Also just noticed some people in this thread that are having difficulty getting the op instructions to work, I figured I would mention what happened to me. A while back I upgraded magisk and which broke my finger print. I used this guide to fix it. Then again later after upgrading magisk and phone upgrade and it broke again but I couldn't fix it no matter how many times I tried. What I didnt realize was I had a few scripts in post-fs-data.d and service.d to automate a few startup things through magisk(things that should not affect fingerprint scanner). I deleted everything in the folder and boom finger print worked again. Very weird to me, so thing with this process breaks the fp. Still need to do OP directions but was good again.