After recent firmware upgrade 9.0.57 for Cosmos, HDMI not working anymore

Cosmos prompted a firmware upgrade after startup. However, after the upgrade, I’m not able to mirror my iMac to Cosmos anymore with either HDMI input ports.

Can I downgrade the firmware? Or any solution to this problem, perhaps?


  • d

Seems this is a question for the support!

@dipzhit try sending an email with what you did and the current fault, they should be able to provide steps for downgrading

Yes, thank you. Will definitely hit them up about this issue.

Hi there,

Please try the following steps to see if any difference could be made with your Cosmos’ HDMI issue:

  1. Try making the connection with another HDMI cable
  2. Try connecting the Nebula with another device(like another laptop, a fire stick) to see if the issue persists
  3. Please make sure the device connected to the Nebula is one of the supported HDMI outputs of the Nebula as listed below:
    1080p 60HZ 16:9
    720P 60Hz 16:9
    1080p 50HZ 16:9
    720x480 60hz 4:3
    1080p 30HZ 16:9
    640x480 60hz 4:3
    720x576 50HZ 4:3

If nothing changed, please contact Nebula Customer Support at for further help.