[Question] DOOGEE DG300 GSM/WCDMA network problem

[Aksom16]

Have you tried adjusting your APN settings for your network?

yes, ive configured my APN. However there is somthing like "Preferred networks" its empty. I tried to get another same model phone and backup the entire rom and install it on my phone, no luck still the same. Can u tell me how can i backup the entire FIRMWARE with NVRAM of the phone? Ive seen some on the posts by other guys, but im missing the CACHE file and the USERDATA file.