[Barnes & Noble Nook Tablet] nmyshkin:
The ROMs

Updated and revised 2-5-23

Generally I disabled any stock stuff I could that I would not use. Anything past CM 11 has a maddening issue I call "peek-a-boo keyboard", most noticeable when using the browsers. The keyboard drops out while you are typing or simply refuses to open without a struggle. You can solve this problem in CM 12 and minimize it in CM 13 by installing Simple Keyboard.

CM 11 is beginning to show expired certificates and SSL issues. You can try replacing or adding new certificates, but it's not easy and you're left with warning artifacts in the status bar. Ditto with CM 12 and CM 13, but they are not nearly as bad--for now. The stock browsers, fortunately, allow you to "ignore" security warnings which makes browsing more pleasant. You may not feel that's a great idea, but the reality is that browsing is the Achilles Heel for all these ROMS, and it's worse the higher you go. The stock browsers may give the best overall performance, whatever their shortcomings.

Because of the SSL issues, I don't recommend CM 11 any longer unless you are not going to do much in the way of internet stuff.

Note: I have noticed that both my Nook Tablets (8 and 16 GB) run better if they've been on for a bit. If yours is cranky when it gets up in the morning, pouring coffee on it won't help, but a little siesta after boot may be just the thing :)

CM 11 (y)(y)(y)(y)(y) (but with issues as described above)

https://www.mediafire.com/?gq1y21uz11lr1c0

Flashed with SD-based TWRP 2.8.6.0, enabled signature spoofing with Tingle

This is arguably the best choice for the BNTV250a if you want something other than the stock B&N ROM. It runs smoothly enough that you could even keep the PlayStore app on it and it would still behave reasonably. It's even better without it. The only drawback with this ROM is that Android Webview cannot be updated. This means that some websites will not display properly or may simply crash, regardless of what browser you choose to use. I found the antique stock browser to be surprisingly good, but Via also works well. Also, the SSL is in need of updating, so you will run into issues with some websites and apps like OverDrive.

The lesson that this ROM taught me is that these tablets are for casual use. You can't just load them up with apps and expect them to run well. Think about what you really would like to use the tablet for. Consider older versions of apps that will probably still have more features than you will ever want but are less taxing to the system. You can see from the attached screenshot how I eventually pared my choices down. I should probably pare it down even more. Most of the apps are older versions and I've kept the total count low, certainly less than on my 16 GB tablet and other devices. You don't want to exceed about half of the internal storage capacity.

CM 12.1 (n) (y)(potential WiFi issue as described below)

http://www.mediafire.com/file/7zxc2e...K6-acclaim.zip

Flashed with SD-based TWRP 2.8.6.0, enabled signature spoofing with Tingle

Edit 9-30-22: I recently booted this up to find that it would no longer connect to my fairly new ATT router. Puzzled, I took the tablet to my local library and had no difficulty connecting there (open network, though). Next I started restoring backups of each of the other ROMs in this list and each one had no trouble with WiFi at home. I installed a fresh copy of the CM 12.1 ROM. It also refused to connect to the router. I scrounged around the web and found two more versions of CM 12.1. Neither would connect to my router. So...I'm not sure if there is some additional security ATT has built into their WPA2 authentication or what, but I mention this just to alert you that this might be a problem. I was even able to connect to a mobile hotspot generated by my Windows 10 machine (password needed). Why this new(?) problem for the 12.1 ROM only, I have no idea.

Before you start installing apps the behavior is sprightly, even on the BNTV250a. As the internal space decreases and RAM use increases, it becomes a little less so. Even so, when running well I think it comes close to CM 11 (with GApps), albeit with more lag.

The stock browser seems like the best bet (I tried many), though it can be slow.

For me this ROM has two major issues. When it is unhappy, it will simply shut down the tablet, literally turning it off. This used to sometimes happen when I ran it on my 16 GB model, so it's not the fault of the BNTV250a. The other issue is problems for apps writing to the external SD card. For a tablet with precious little internal space, you just don't want apps downloading into internal space or storing lots of data there. There is an edit to the file /system/etc/permissions/platform.xml which corrects this issue for some apps. Find the section of platform.xml below and add the last line:

<permission name=”android.permission.WRITE_EXTERNAL_STORAGE” >
<group gid=”sdcard_r” />
<group gid=”sdcard_rw” />
<group gid=”media_rw” />

This change enabled OverDrive and Kodi, for example, to download files to the external SD card. It might work for others.

Not as fluid as CM 11, but WebView issues are gone and you can access most up-to-date content (if slowly).

CM 13 (y) (y) (y) (y)

https://archive.org/download/cmarchive_snapshots/cm-13.0-20160819-SNAPSHOT-ZNH5YAO0IN-acclaim.zip

Flashed with SD-based TWRP 2.8.6.0, enabled signature spoofing with Tingle

Never having tried this ROM on my 16 GB tablet, I was actually pleasantly surprised by its behavior on the BNTV250a. There's a funny WiFi thing where if you leave WiFi on when you shut down and then boot up again, it will not automatically connect (unless the lockscreen has come on, which is pretty fast after booting, so no biggie). Otherwise it's pretty much like CM 12 although maybe a little more stable--if you don't overdo it. The Sound Recorder app is somehow broken on the CM 13 ROM. If this is something you'd like, you can replace the broken version in /system/app/SoundRecorder with the one attached below. Make sure the permissions are rw-r-r and reboot.

Some apps can't write to the SD card (as portable storage). Kodi is an example, I'm sorry to say. I've tried many "solutions" to this problem but the only one that worked for me is to edit /data/system/packages.xml, adding the permission for each specific app you want. This is a long file and I did this using the editor from the CM File Manager. There are probably easier ways. After locating the app you want in the xml file, add this line anywhere between the <perms> and </perms> tags:

<item name="android.permission.WRITE_MEDIA_STORAGE" granted="true" flags="0" />

This change will be overwritten if the app updates, so you might want to keep that in mind.

This is the ROM I've settled on for my BNTV250a (screenshot of home screen below)

AOSP 6.01 "Marshmallow" (n)

Box

notredame.app.box.com

(you want aosp_acclaim-ota-MOB30Z.160820.zip)

Flashed with emmc-based TWRP 3.0.2-0, enabled signature spoofing with Tingle

This is one of the ROMs built by @amaces. The AOSP builds are very lean compared to CM ROMs so I was hoping this might perform somewhat better than CM 13. But I don't think it does.

The first big hurdle is enabling root. My thanks to @digixmax for pointing out the right tool. After first boot (or maybe even before, but I did it after) you need to flash UPDATE-SuperSU-v2.46.zip. Works perfectly.

The stock launcher is, well, funky. I replaced it with Nova Launcher but after installing a few other apps it was clear the system was under great stress. Lots of black screens and crashes. Not a good option for the BNTV250a.

AOSP 7.0 (n)(n)

https://www.mediafire.com/?5vcw8l603d3r5sc

Flashed with emmc-based TWRP 3.0.2-0, enabled signature spoofing with Xposed

This is another ROM by @amaces and what I run on my 16 GB tablet. On that device it is virtually flawless. I really wanted to say the same for the BNTV250a, but I can't.

Enabling root for the ROM is achieved with Magisk.

The ROM appears to be odexed to Tingle and so you must flash the correct Xposed (for 7.0

and

Magisk) and install the installer app along with the FakeGapps app as described in the previous post.

The stock launcher is pitiful and you need to install a root file manager to get anything done. The system is laggy and

video is not smooth

. Not even a potential option for the BNTV250a.

Lineage 14.1 (n)(n)

Box

notredame.app.box.com

(there are many versions of this ROM. The link takes you to the "obsolete" folder where you need to hunt down lnos_acclaim-ota-NJH47F.180211.zip. This seems to be the only version without the shut-down bug)

Edit 2-5-23: Well...no, it does not have the classic shut-down bug (tablet reboots right after it "shuts down"). Instead, it often shuts down just fine, but occasionally locks up during shut down and has to be forced off with the power button.

Flashed with emmc-based TWRP 3.0.2-0, enabled signature spoofing with Tingle

This is a third ROM built by @amaces (his most recent for the NT). I didn't have much hope for this because if 7.0 was an issue, I didn't expect 7.1 to perform well.

The only native root capability is for ADB. To enable full root, you need to flash addonsu-14.1-arm.zip (attached below). I did that after first boot but perhaps it can be done along with the ROM.

Not surprisingly the ROM has the feel of CM. There appears to be a file manager but it is only a partial reflection of the native file explorer and is useless for the manipulations that need to be done, so you need to adb install a root file manager as described in the previous post.

The stock browser is complete rubbish. It looks to be Gello(?) but it is the most infuriating collection of electrons I have ever encountered. There are no navigational buttons, no bookmark button--no buttons at all! I really tried. I used gestures (some rude), I tried magic words (many of which do not appear in children's books). Nada. When I finally managed to reach my test site it was like wading through, well, Jello! So....attached below is the nice lightweight stock browser from AOSP 7.0. Navigate to /system/app/Browser and there you will find Browser2.apk. Rename it to something else and copy in the Browser2.apk attached below, setting file permissions to rwx-r-r. Reboot. If you are successful, you can delete the old, useless browser apk. To enable bookmarks, navigate to /system/app/BookmarkProvider and inside you will find the apk file. Tap to install. I don't know why this needs to be done, but it does even on AOSP 7.0. Reboot and you've got a functioning browser (rife with "peek-a-boo keyboard")

The ROM hates Kodi, crashing constantly.

Video from other apps is not smooth

. Not a viable choice for the BNTV250a.

For a lark I tried it on the 16 GB model and it's actually not bad, but then I saw that embedded browser videos (like YouTube, for example) were funky colors, so... It may be that later versions corrected this, but those likely have the shut-down bug. In any event, a terrible choice for the 8 GB model.