T20 bought at second hand store. Unable to reset it.

[Jeff771]

The admin password has been changed and I am unable to reset it. From what I have read on these forums it sounds like I will be unable to get the rfs and bin files. I have no paper work for this phone and have no idea what distributor it came from.
Is this case? How do I find out if this phone was issued by a carrier?

[Lucia_Yealink]

HI Jeff，

Please refer to the FAQ below:
http://support.yealink.com/faq/faqInfo?id=433

About how to do auto provision, please refer to the guide below:
http://download.support.yealink.com/down...V73_40.pdf

Any question, please let me know.

[Jeff771]

I have verified the version, the 3rd number is 0. I have followed the instructions but I am still unable to log into the phone. When I hold down OK and get the "Reset to factory settings" prompt I hit OK and I get prompted for the user name and password. I have tried to log in via the GUI and I am unable to log in with the password admin.

[Lucia_Yealink]

I can show you a solution to change the password without resetting the phone, steps as below:
1. I attached a .cfg file for you, which has a simple parameter:
static.security.user_password = admin:admin
2. put this file on your provision server(in my example, I use HFS as my local server)
https://ticket.yealink.com/BugFile/image..._84031.jpg
3. long press a line key, and choose the Type as key Event, Key Type as Zero Touch:

4. after this linekey is set, press it once, you will see below screen, and then press OK-->next


5. when you see below screen, input the URL manually-->press OK


I know this is not a simple solution, but please note that, customer just need to set this line key once, if he meets same issue again, he don't need to input the URL again.

Please have a test on your side, and let me know if any misunderstanding.

[Jeff771]

Thank you. I am unable to find your attachment. I have set up my own 1.cfg file and updated the line "static.security.user_password = admin:admin".
My phone is downloading the new cfg file but the "admin" password is still not working.

[Lucia_Yealink]

Ok, sorry to forget to attached the cfg files.
Since the T20 is an old model, and the parameter below is for version 81:
static.security.user_password = admin:admin

So you must use the parameter which is fit for V73:
security.user_password = admin:admin
please download the attached cfg files and to do auto provision.

[Jeff771]

I was able to reset the phone with that cfg file. Thanks Lucia!