Beagle Bone Black fails to start flashing.

I try to flash my beagle bone black but while the button is pressed, voltage in the input goes off, and can’t get started to it. I changed several times the power source and the SD card. To put it even worse, since this wasn’t my card, I don’t know the password, nor the distro it has installed.

I’m trying to install on this Ubuntu, and beagleboard.org led test is working fine.

Thanks for any help in advance

Regards

Well... Do you have a usb-serial adapter to plug into the serial
header??? Such that we can see what's going on?

Regards,

Yes I’m on it. In fact I finally gain access to the board from ssh.

Regards