Unable to login due to the password change

[pine_usr]

Hello everyone,
I just have a quick question. Just got my new Pine64 UBports edition phone and after booting the phone first time I was prompted to enter a screen lock pin, which I did and chose 4 digits pin. After I boot into the UBPorts system, played around, opened terminal and went ahead and changed password for the main user by passwd command. After a while the screen was locked and in order to unlock it, you get a prompt to enter password. The initial 4 digit pin is not accepted, since I changed password. But, there is no way to enter new password (letters and digits) as the prompt only has digits option. There is no way to enter a new password which contains letters. I wasn't aware that the new password for the user will also apply as a screen unlock PIN. Now, I am stuck with no way to enter the system and need to reset it. What is the fastest way to factory reset UBports without full reinstall? Pressing Up Volume + Power Button get me "Installing update" screen which never disappear. In regular Androind phone you login to a bootloader and just factory reset system. Could anyone suggest how to factory reset UT system instead of full reinstall? Also, why screen lock pin is the same as a user password?
Thank you.

Hey @pine_usr ,

I did the same thing!

Easy fix if it is an sdcard OS:

1. 1st turn off phone.
   
2. Take out sdcard.
   
3. insert/mount sdcard for editing
   
4. backup /etc/shadow by renaming it /etc/shadow.bak or something similar
   
5. move /etc/shadow- to /etc/shadow to replace (/etc/shadow- is a backup of original)
   
6. put sdcard back into phone
   
7. login with original default number
   
   Outside that you can try to do the same remotely logging in if not running off sdcard.
   

As I mentioned in my initial post the OS installed on eMMC internal card, not sdcard. How renaming /etc/passwd file can help to login with initial only digits PIN?
Can any one provide clear solution for resetting / factory reset of UBPorts in order to be able to login into installed on internal card OS. There is still no clear solution for this seemingly common problem people have. I've noticed another post with the same problem. How in the world developers did come with the solution to use screen lock same as the OS user password and didn't think about providing a normal keyboard layout for entering password?
Again, no clear solution, any help to resolve this issue would be appreciated. Of course, flashing/reinstalling/booting from sdcard would help, but there should be easier solution to this problem.
Thanks.