Background: I've been running CM 10.2.1 for a few weeks now. Given what Jon Lee posted about Google and security, I thought I'd try a clean install of CM 10.2.1 without installing gapps, just to see what that's like. (And what services don't run.)
So I did the usual "factory reset" from TWRP and reinstalled CM 10.2.1. To my surprise, when I booted, the latest version of Google Play was still showing on the launcher!
I had used Link2SD to integrate the latest version of Google Play with the OEM system app. So apparently, that this was not wiped. And of course, internal media data is not wiped (not by TWRP, anyway) in a factory reset. But I thought /system was.
The TWRP FAQ has a page about wiping. It says
Depending on your device and its configuration, you may have options for wiping internal storage, external storage, sd-ext, android_secure, and/or an option for formatting data. There's almost no reason that you would ever need to use these items. These options are there for convenience. For instance, if you're getting ready to sell your device, then it's a good idea to wipe everything on the device so that the new owner doesn't get your private data.
TWRP makes it confusing by offering to 1) wipe data, 2) internal storage, 3) SDcard or 4) SDcard data in Advanced Wipe. Which is it for wiping your media stuff?
From what I've read, "internal storage" should be the same as "SDcard." So why both? And how is "SDcard data" distinct from those two?
To make matters worse, in the Nook I thought there was an additional element of confusion because the Nook doesn't call the internal SDcard memory what everyone else calls it.
So let's say I am selling my HD+. Would I select all of the above and still be able to install a ROM clean?
Or would I brick?
I know that on a desk top computer if you want to start bare metal, you format the hard drive, wiping everything, and install onto that. But judging from what Succulent wrote in his blog about recovering from an EMMC crash, you can't start totally clean with Android. Apparently, Android needs some preexisting files on the "drive" in order to install. (Like the devconf folder, which contains your MAC and your serial number.)
[Am I understanding him correctly? He was talking about recovering from a tablet wrecked by the EMMC brick bug. Perhaps no /data partition at all, as he offers a script to rebuild/expand that partition?]
I have read stories of people bricking their tablets by formatting /data from CWM. I don't understand why that should brick it. Why couldn't you boot into recovery? How can the /data partition affect the /recovery partition?
So - has anybody done a complete wipe on their Nook HD+? Please explain, for those of us who are obsessive compulsive, exactly how you do it.