Blinking black and blue screen hdmi hookup
I assume you talk about laptop
Then i assume you laptop GPU does not not detecting you cracked display - then you have blink coloured screens
And hooking HDMI with zero result is BAD GPU or you have cracked LCD - LCD cable problem - shorten or just disconnected from the mobo of the laptop
Try reconectring LCD cable to the cracked LCD or remove it compleatly ......
I hope you GPU is OK ......