while attempting to root my Blackview BV6000s (containing Mediatek MT6737T chip) I lost both IMEI's. Although I succeeded in rooting the phone, I was not able to restore the IMEI.
1) If I use Mediatek Engineering apk, when I send the string "AT+ EGMR=1,7,"IMEI_1″ I receive the error "This Command is not allowed in user build". I have read a lot of forum posts where they say to put a blank after "AT+", but it doesn't work placing the blank in any place: before or after the "+", or without blank at all. Always the same result: "This Command is not allowed in user build". I have tried all the versions of MTK engineering apk that I found inside and outside google play store
2) It is not possible to get any connection with "MTK Droid tool". Same result with MauiMETA
3) With SN write tool, when I plug the USB cable the phone powers on and the Blackview logo is shown, and after few seconds a red "FAIL" message is shown by the SN writer tool. It seems that the phone is not able to enter in "meta mode"
4) I have generated an IMEI file named "MP0B_001" and I have copied it in the right place with the root browser, but after the reboot the IMEI are still empty. I remark that when I try to set the write permissions, the root browses pops up an error message saying that the file system doesn't allow changing the permissions of the files. Then I packed the MP0B_001 in a zip file and I installed it with the TWRP recovery. The installation with TWRP doesn't show any error, but then after the reboot the IMEI are still invalid (null). Note: in ALL the posts that describe how to install the MP0B_001, they indicate /data/nvram/md/NVRAM/NVD_IMEI/MP0B_001 as the path where the file is stored. But in my phone the path is different, and precisely it is /nvdata/md/NVRAM/NVD_IMEI/MP0B_001. This makes me think that nobody have tried to apply this procedure to BV6000s. Anyhow, I tried to pack and install the zip with both paths, with the same unsuccessful result.
5) The only way I could write something in the 2 IMEI's is with Chamelephon. However there must be an incompatibility between Chamelephon and my phone. In fact, after applying the new IMEI's and rebooting, when reading the IMEI I find random strings instead of null strings. What is odd is that one of the 2 SIM cards succeeds in connecting with to the mobile networks and receive calls and SMS, even with this corrupted IMEI, while the other SIM still gives "invalid IMEI" error. I tried to find newer versions of Chameleon, but it seems that only version 1.0 exists
6) I tried to install all the ROM's that are compatible with MT6737T but the results of attempts 1-5 are the same.
In conclusion, it seems quite impossible to fix the IMEI. I have the impression that nobody tried to fix the IMEI on this specific phone, or that the producer has decided to "punish" whoever tries to root the phone, by preventing the repairing the IMEI. All the forum posts and guides, on which I based the attempts that I have described in this post, are not referring explicitly to BV6000s. Before resigning myself, I decided to create this post. Maybe it could be helpful also to other persons, if a solution exists and is described here.