Hello hunter86_bg, you just save my life phone, i want to thank you for your post, it help me a lot!
I got a BV8000 Pro, and i upgraded to the oreo android 8 via OTA, after installing and flashing the device, everything worked fine...except the calls and sms, so i check out the imeis...and surprise...all 0000000 zeros insted! So i search for a solution.....a real devastating search with no avail.....or programs didnt work fine or would do nothing at all, not even read the phone! Then i found a solution here in the blackview forum....your solution..... i try others because the device its diferent from yours, but i try your solution and it was the only one that worked without fault....perflectly! So my friend i am in eternal gratitude to your kindness to help me and other users here! Thank you again my Friend for your help!