This one. Seriously. It seems to a well made generic (presumably Chinese) cable sold by lots of different vendors. I just Googled 30cm HDMI cable. FWIW, I tried it with a cheap 2m cable and that worked fine too…
https://www.amazon.co.uk/gp/product/B00DNSP6XC/
Remarkable similarity to this one sold by the US Holo Audio distributor, Kitsune, no? 