A few months ago, I used Endpoint Manager to set a custom background image on a number of our phones (Yealink SIP-T54S and SIP-T54W), and now want to revert to the default background. This was simple enough for the SIP-T54S. Edit the associated template, under Options > Background Image select None and Save/Rebuild Configs/Update phones. This didn’t work for the SIP-T54W. I also tried editing the template basefile (through Endpoint Manager), adding the option:
phone_setting.backgrounds = Default.jpg
I also tried
phone_setting.backgrounds = Config:Default.jpg
Even after I Save / Rebuild Configs / Update phones, the previously-set custom background image persists on the phones. Any suggestions, besides manually accessing the web interface for each phone and selecting the default wallpaper?