Can I understand it this way:
For legal reasons, even though we are using the latest OTA, the firmware will not be updated to the oneplus one. So we need to manually update
The current OTA is based on CyanogenMod 13, which is too old, and some functions may not be well supported. So it is necessary to update the firmware.
The update method is to extract the firmware from the official original installation package, and then update it to the Android directory through the adb tool.
I don't know if the above understanding is correct, because I just started to study Ubuntu touch recently, I can understand the basic concepts, and some details are not very clear.