Just to echo what a few people have said elsewhere and clarify something. Using an SDcard with a UHS classification may well cause your HD2 to hang, black screen, freeze, crash .... especially when using certain ROMs. Some seem more resilient than others, but the NativeSD ROMs in particular rely heavily on accessing the SDcard. The only way to reset after a blackscreen is to remove battery and reboot.
The HD2 was never designed to work with these cards and they require specific voltages from the phone hardware in order to run correctly. The HD2 does not have such hardware. I used a Sandisc 16GB Class-10 UHS-1 card and my phone would hang/crash 7-10 times each day. After replacing it with a Class-10 Kingston card with no UHS classification, the phone runs fine. Nothing else was changed except the SDcard. The exact same installation was used by cloning the SDcard partitions. Consequently the phone runs fine now.
Just thought I'd post up in case it helps others.
Would appreciate if someone could mirror this post for me (I have less than 10 posts on XDA and don't want to spam the forum just to get them) on this thread
for [ROM][4.1.2][720p] NexusHD2-JellyBean-CM10 V1.5 [NativeSD]
because a few people were complaining of bugs and it's nothing to do with the ROM itself, more the memory cards they are using.