Final status after startup

After uploading the firmware 20170517_s12v55_jk_3m, the BV6000 communicates, but the system does not start. The display switches on with the Blackview inscription. I'm sending a memory test.

Nothing resolved I have used your OTO update - then interrupted calls. I have done according to your instructions to update the older version. Result: Phone is dead (nothing works) Your link to the manual is not working (can not connect). The conclusion is: - you are not able to know, what to do - y...

For information I give:
The computer does not know, when connected to the phone.
The PC responds to the phone only after pressing the FTT button and then installs the driver - MTK USB port (com4)

Is there some way to communicate via VCOM ?

Otherwise, the phone is completely dead.

Everything went according to your instructions. The result is bad. The phone is already dead after uploading the new system (by Sp Flash Tool). It can not be turned on and no buttons are responding. My Phone is 6 months old. I have no phone since I started last update ROM BV6000 _Blackview_V01_20170...

I updated the ROM via OTO, I can not make calls because the calls are interrupted after 1-3 minutes.

I need to return to the earlier version of ROM. Can you write a return procedure?

Otherwise, the phone is on disposal.