If you still use your nook HD+

Hi,
I still have 2 nook HD+ tablets that I have installed android 5.1.1 on. They do not run well. Many apps won't open. The screen goes black and I end up having to hold down the power key until it reboots. I do know that it's old hardware, but I see others here saying that theirs is running great. What firmware are you using? I may return to stock firmware if performance will improve. I'm just trying to get a little more use out of them. They had better resolution than the new fire tablets, so I figure we could use them when we go camping instead of bringing our good stuff out there.

Sorry if this was the wrong place to post this.

Penny