Hey guys!
Sorry for bringing up this topic again, but i have the same bootup issue as mentioned before! I have a brand new eyesy and it does the following:
I did check all mentioned possible things:
I don´t know what to do 
Thanks in advance.
Do you ever see the word ‘EYESY’ displayed after the colorful, rainbow gradient screen?
Have you tried booting with the composite video output?
hey, thank your for your quick response.
No - the Logo doesn’t show up and i didn’t try the composite output.(unfortunately i don’t have any devise with composite input).
Hey chrisk, is there anything i could do to solve this? Greetings <3
Just sent you a PM
would probably be helpful to post the response for the record 
Same symptoms here.
Can you share how to fix this?
Hi, the first thing to try is to reburn the OS on the microSD card. Instructions are here:
https://www.critterandguitari.com/manual?m=EYESY_Manual#61-burning-sd-card-disk-image
This worked for me as well.
My EYESY worked perfectly…yesterday. I was all excited to dive into some tutorials/exploration/Mode development, but today, all I get is the “rainbow” - full screen - no OSD - LED appeared blue during start up, now “off” (???) - but the rainbow remains on screen. Must I really reburn the OS? After one (first) day of use? Hoping for something else.
UPDATE: This worked (burning SD Card Disk Image as instructed) - whew! How often will we need to do this? Was it something I did to cause this issue to happen? If so, what might I have done (I’d like to avoid in future).
Thanks again. I love EYESY.
Make sure you power down the Eyesy properly - allow the status LED to turn off before disconnecting power. I know that other Raspberry PI based projects can corrupt their system image on the SD card if not powered down properly - I assume Eyesy has the same potential problem.
Hope this helps,
John
This really helped me! (even the pro tip about being careful while adding/remove the microsdcard, I had to unscrew the back to remove my microSD card) Thanks y’all. Super excited for this machine!
Peace
Followed the instructions to reflash the sd when my eyesy started doing the rainbow screen thing and it worked. Thanks for the help!
Before you flash, it might help to unplug the WIFI dongle. To me it looks like the EYESY will try for quite a long time to connect to a previously configured WIFI access point - if it is not reachable, you might stay with the rainbow.
At least, for me this helped. Just turned off 2x after 10+ minutes of rainbow, unplugged the dongle and it came up again very fast.
EDIT: and thus, I’m locked out, as there is no WIFI, and so, no connection. Powerup and SHIFT doesn’t seem to help neither. Any ideas anyone (besides flashing)?