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After rebooting my rooted, unencrypted, android phone, the lock screen keeps telling me my password is wrong. But I am very sure that the password is correct. Because I input this password once per day. I have adb debug enabled and I can connect this phone to computer, what can I do now? I don't want to reset my phone, that will lose my data. Thanks a lot.

PS: Another weird thing is even if it keeps telling me my password is wrong, after attempting this correct password many times (more than 30 times, I didn't count), there is no password failure attempts warning at all.

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  • Is the password prompt the regular lock screen or the mini-OS after boot that allows you to enter the FDE encryption password? If it is the latter the expected password may be different from your lock screen password. Both can be changed independently on a rooted device.
    – Robert
    Aug 25 '20 at 7:11
  • @Robert the phone is not encrypted at all. So no FDE. Just a regular lock screen. Because the phone is 3 years old and battery is not very well, I keep rebooting the phone about every two days and thus I does enter the password every two days. I am quite familiar with this rebooting and entering lock screen password process. But today, it's just weird day and the system no longer accept my correct password anymore.
    – sgon00
    Aug 25 '20 at 7:16
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    guess some file corruption caused this. ext4 journaling file system is not the best choice for eMMC NAND flash memory (even if it's just one upper layer, and the drivers already provide smart underlaying wear-levelling) - be prepared for more failures in the next months and dead eMMC in the end
    – alecxs
    Aug 25 '20 at 10:36
  • @alecxs Thanks a lot for telling me the possible cause. I thought it was hard drive (NAND chip) issue too. Does it mean my NAND chip drive reaches the end of its life? Does it mean the phone will become a rubbish soon? Since the NAND chip is built-in, it's not easy to change the NAND chip. This is the second phone I met such issue. Does phone have so short lifetime? I can use my more than 10 years old laptop today, but can not use more than 2 or 3 years phone.
    – sgon00
    Aug 25 '20 at 12:05
  • yesterday a friends Galaxy J6 (2018) died out of nowhere, right after 25 month (24 months warranty). can't even reach recovery or download mode, it always boot loops on splash screen when holding volume dn + power for 10 seconds. i told him it's a brick
    – alecxs
    Aug 25 '20 at 12:15
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I found a working method in XDA article 1 and XDA article 2. It's lucky that my android phone is rooted, so I can simply remove the key files and reboot :

adb devices
adb shell
su
rm /data/system/*.key
rm /data/system/locksettings.db
rm /data/system/locksettings.db-wal
rm /data/system/locksettings.db-shm

One more thing which bothered me is I have no ideas what the problem really is at the beginning. I did see some online questoins regarding the same issue such as link, but so far, no one can provide a logic explanation about this issue.

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  • only for devices where login credentials not involved in encryption
    – alecxs
    Aug 25 '20 at 10:38

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