Reading the release notes, the latest firmware for the HD-AV on the Z15-BMPCC is 1.18.
With the Zenmuse Assistent 1.4 I can't upgrade from 0.7. Pressing 'no updates' and then the refresh button doesn't help.
Do I have to use an older version of the Zenmuse Assistent? Where can I get one?

ok, I follow up myself.
Even with software 1.1 I can't update the HD-AV Firmware.

As I now see, this results in a black screen on the HDMI port of the Lightbridge. Only OSD visible.
On IOS / Android devices I got a perfect camera picture.
The camera connected to the HDMI port on the Lightbridge makes a perfect picture, even on a HDMI monitor.

So it seems that the HD-AV converter is broken.

no answer? disappointing for a support forum.

alexander.sucke Posted at 2015-6-9 18:04
no answer? disappointing for a support forum.

Hi, just on more confirmation, have your login the assistant?
2. When the video is black screen, how does the gimbal LED flash?

The gimbal-LED right on the HD-AV board is blinking green.
Login in the assistant software is the same as on the a2, iOSD and lightbridge assistent software.

meanwhile I replaced the 6 and the 9 pin cable with spare ones, without success .

alexander.sucke Posted at 2015-6-9 18:04
no answer? disappointing for a support forum.

While DJI people are often here this isn't a direct line to support, per se. If you're looking for official support best to call official support...