Just to revive this thread...

Been playing 2160/24 and 2160/30 demo videos through the HD621 this morning, without issues, using a HiMedia Q10. Sound was only 2CH PCM however, so perhaps multichannel PCM on top of 2160p breaks the camel's back?!

So, if you can find a way around the HDCP 2.2 handshake, it seems the HD621 will happily play UHD blu-ray and the like.

My Music : My Cinema