In this video we go over how to unlock a Yealink SIP phone which has an unknown administrative password applied thus preventing a successful factory reset. We will show how to get past this problem by putting the phone into a factory firmware recovery mode and upgrading the firmware via a USB key. Furthermore I will show you how to get the phones' MAC address removed from Yealinks' Remote Provisioning Service (RPS) database to prevent the service provider assigned admin password from being automatically reapplied again. The IP phone model we illustrate in this video is the Yealink SIP-T42S, or just T42S. But the procedure should be the same, or similar, for the following other Yealink SIP phone models as well: T46S, T48S, T27G, T41S, T54S, and T52S.

NOTE: Yealink has removed the firmware recovery files from public access now. So you will have to open a support ticket (same process as removal from the RPS database) to prove ownership first in order to get access to the recovery files I showed.

The eBay and Amazon search links below are paid links, for which I may be compensated and earn a commission, if you choose to buy the parts and tools shown in this video thru them:

ADATA USB key: https://ebay.us/DJeTSR or https://amzn.to/3O6zB2p

Used Yealink SIP-T42S IP phone: https://ebay.us/GMiXpV

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Chapters:
0:00 - Problem overview
1:15 - How to perform firmware recovery via USB

Corrections:
4:34 - Yealink has decided to hide these files since this video was made. You will have to open a support ticket to access them from now on.

#drshock

Disclaimer: DrShock, the alias for the human content creator for this YouTube channel, is not responsible for any damages, injuries, losses, or liabilities associated with any repairs, upgrades, or maintenance performed on yours, or any other, product whatsoever. No warranty, express or implied, is made as to the accuracy or completeness of any information provided within this channel. Viewing and using the “as-is" information of this channel is totally at your own risk. Always wear personal protection equipment and follow appropriate product manufacturer service manual guidelines with original manufacturer parts only when performing any repairs, upgrades, or maintenance upon any product.