版主死心吧
CISCO官方文件有說
僅能由第三方Firmware 升級至CUCM專用版本
不可逆向操作
請參閱文件146頁最下方說明
Enable Enterprise Image Upgrade
The Cisco IP Phone also supports a single image upgrade from 3PCC image to enterprise image.
Default: No After upgrade to enterprise image, the phone cannot revert to 3PCC.