[Nook HD, HD+ General] wayover13:
I understand vaguely what you're talking about here, but I'm pretty new to flashing Android devices and find myself wanting to know more. Is there some link you can point me to that explains in greater detail about dirty versus other types of installations? What I'm most interested in learning is how much configuration is too much to permit a dirty install. For example, the tablet is of little use to me if I can't install certain apps on it; will installing apps, for example, obviate the possibility of the sort of dirty install you're speking of?

For example, I want a battery percentage monitor in the taskbar. If I enable that, is that the sort of user interface change after which I will be unable to do a dirty install? How about deleting what I would call desktop icons and/or adding others from newly-installed apps? Is that the sort of user interface change that will cause me to be unable to do a dirty install? If so, it seems like I would need to become a sort of beta tester in order to retain the possibility of doing further dirty installs, rather than using my Nook for my everyday needs.

I'm obviously not too well versed in CynaogenMod/Android development. I wasn't aware that CM-12.1 was at such an early stage of development. Let me see if I'm, understanding correctly: is the CM-12.x series tracking Lollipop, while the projected CM-13 will track Marshmallow (Marshmallow being, as I understand it, the next Android release)?

I've obvioulsy got a lot to learn on this front.

---------- Post added at 11:24 PM ---------- Previous post was at 10:55 PM ----------

Yes, on a second attempt I realized I needed to hit the move-back trinagle to get to the reboot button to which the manual was referring. Thanks for the clarification.

You're right. I should have kept reading :(

On my second try, I realized I'd noted another discrepancy in the manual, one that occurs between steps 5a and 5b. After step 5a (successfully booting to TWRP by holding the power and home buttons down for the correct interval) I actually get an "Unmodified System Partition" screen. There, I have the option of either keeping the system partition read-only, or swiping another option to allow modifications. It is only after either tapping the read-only item or swiping the allow modifications item that I get a subsequent screen where I can tap the Install button (step 5b).

I have a fair amount of experience writing image files to disks/partitions. Does it seem like that's what's needed? I also know how to mount an image file as a looped file system in order to, for example, copy files from it. That's something like what was done with the unrar'ing of CWM and copying files over to the SD card. If any of that experience sounds helpful, I could probably conduct some experiments to see if I could succeed at this. I'm just not sure what the TWRP image file I found is: is it a bootable image? If so, I'm not sure copying files from it to a bootable partition, like you instructed to do for CWM, would work. Writing a bootable image to an SD card should, on the other hand, cause that SD card to become a bootable medium.

In any case, as I said, I could conduct some experiments if it seems like any of my suggestions would be helpful. I'm not really any kind of professional either, btw. I got into computing when I undertook, at a later stage of life, some graduate studies in the humanities, during which I developed the crazy notion that I could somehow gain the upper hand over the machines. That attempt ended in failure, but I have kept up my doomed insurgence and learned some things along the way.