Okay, I found software that allows me to flash the firmware
"hikvision tool manager" "batch software" but it still doesn't work
firmware IPD_R7_EN_STD_5.6.0_190128 stops at around 10%
firmware IPD_R7_EN_STD_5.6.11_190426 stops at around 20%
of course all other firmware before or after don't work
I'm going to stop there for many hours looking for a solution.
fortunately I can still manage the camera by synology surveillance station
hikvision makes good cameras, but the firmware management is catastrophic
never buy from them again
Thanks for trying to help me