Problem to flash Lenovo A390t

Hi I have some problem with flash two lenovos type A390t. System has crashed and says after boot failure decryption and recovery not working. Only what i can do is that I get with volume down+power button to safemode and then throw adb reboot into bootloader (after reboot shows fastboodmode) and here with command "fastboot flash" is say send okay and on writing is doing someting but hours is a long time it seems that he cand find a way where to flash. A attached picture
With Spflash tools is notworking because when I connect it to the phone in hardware shows just unknown device( I have all mtk driver, and try everything), it seems that here is bad preloader in mobile or missing here. I spend a lot of hour and nothing. Thank you, have a good day :)