On some certain models mostly the MTK models, you can connect while the device is powered off and on some models you'll need to connect the phone while in 'download mode' -(connect the phone to a charging source then hold vol up + down + power button to boot to download mode)
SE_ERR_ADB_CMD_GET_FAIL_RESULT -- if you encounter this error then you need to unlock bootloader before proceeding. Unlock command varies on different models. Search online for the right command or how to unlock bootloader on your model
Patched versions do not require internet connection, whereas non-patched versions require internet to connect to nokia servers
Non patched versions require that you have an authorized after-sales account to login