Reading at the wiki here ubuntu touch install wiki and going to see the supported devices I read that for the "production" devices (like mine meizu pro 5) an adb enabled recovery should be present on the device, as better explained here Adb enabled recovery My question is: have I to install this recovery only if I need manual update/channel shift, or it's a mandatory part to complete the installation process with ubuntu-device-flash command for my device?
thanks luckj