Reviving an ancient Google (Asus) Nexus 7 [2012] (WiFi) (“grouper”) tablet

Nexus 7 [2012] running CyanogenMod 12.1 (Android 5.1.1)

I’ve had this thing for more than a decade. Stopped using it when it updated from Android 4.x to 5.x and became unusably sluggish. At one point, I evidently unlocked it and installed Linux (LineageOS probably) onto it, but that wasn’t really usable on the 7" screen either, so it sat. I tried a couple of times half-heartedly to restore it using the built-in utilities, but never got anywhere and wasn’t honestly that interested, so it sat in a pile ready to be e-waste recycled. (The Fire tablets I’ve picked up over the years are going that route though, except for the one I’ve used semi-regularly with its “waterproof” housing, as they don’t seem to recharge and won’t turn on. Meh. OTOH they were disposable-cheap. But I digress.)

I was stuck waiting to be called via remote court this morning (75 minutes) and, inspired by a Facebook conversation I’d had with a friend who’s also a bit of a geek, I decided to see if I could breath some life back into the thing.

I did.

First, I had to figure out which Nexus 7 I had; it was easy once I learned the 2013 version has a camera on the back (mine doesn’t), so, I have the 2012 O.G. model (Asus manufactured, NVIDIA Tegra 3 platform, with a 1.3 GHz quad-core Cortex A9 CPU, Nvidia GeForce ULP GPU, 1GB RAM, 1280×800 (WXGA) IPS LCD screen (213 ppi), with 8GB storage, Bluetooth 3.0 (I don’t think I’ve ever seen that Bluetooth version before!), 802.11 b/g/n 2.4GHz WiFi, and a 1.2MP camera).

I couldn’t find any factory images on the Google developers’ site (oldest they had was for the 2013 version of the Nexus 7), so I ended up with a CyanogenMod 12.1 (Android 5.1.1) build, (cm-12.1-20161016-NIGHTLY-grouper.zip) fortunately still online here: https://cyanogenmodroms.com/grouper/ Loosely followed the steps outlined at that site, as follows...

Downloaded the Mac version of the SDK Platform Tools, which gave me the adb and fastboot tools.

Hooked it up with a USB A / micro B cable to my 15.4" MacBook Pro (currently running Monterey).

Powered the Nexus 7 on by holding down the power and volume up and volume down buttons until I got the boot splash screen. Selected “Restart Bootloader” from the utilities screen. Once the tablet was running again, made sure the Mac could see it:

flying-geek@The-154 platform-tools % ./fastboot devices

015d2109f04c180d fastboot

The OEM unlock step wasn’t necessary, as I’d already unlocked it a long time ago:

flying-geek@The-154 platform-tools % ./fastboot oem unlock

(bootloader) Bootloader is already unlocked

OKAY [  0.019s]

Finished. Total time: 0.020s

I needed a ROM image to get the device to boot, and fortunately found an archived copy of recovery-clockwork-6.0.2.3-grouper.img from this site. Flashed it to the tablet:

flying-geek@The-154 platform-tools % ./fastboot flash recovery ../recovery-clockwork-6.0.2.3-grouper.img

Sending 'recovery' (6528 KB)                       OKAY [  0.820s]

Writing 'recovery'                                 OKAY [  2.144s]

Finished. Total time: 3.080s

Rebooted again with the three-button process, and selected “Recovery Mode” with the volume buttons. A long-ish press on the power button selected it.

Then I pushed the ZIP file I downloaded (the CyanogenMod build) to /sdcard on the tablet:

flying-geek@The-154 platform-tools % ./adb push \

  ../cm-12.1-20161016-NIGHTLY-grouper.zip /sdcard

../cm-12.1-20161016-NIGHTLY-grouper.zi...1.3 MB/s (221989396 bytes in 166.438s)

Rebooted the tablet (again with the three buttons) back into Recovery Mode.

From the ClockworkMod Recovery v6.0.2.3 menu, selected “wipe data/factory reset”

Once done (“Data wipe complete.”), back to the recovery menu and selected “install zip from sdcard”

Selected the CyanogenMod build (cm-12.1-20161016-NIGHTLY-grouper.zip):

And when prompted, confirmed the install by using the volume keys to move the cursor line down to “Yes - Install cm-12.1-20161016-NIGHTLY-grouper.zip”:

Then watched the status messages as the build was installed:

-- Installing: /sdcard/cm-12.1-20161016-NIGHTLY-grouper.zip

Finding update package...

Opening update package...

Installing update...

Warning: No file_contextsdetected filesystem ext4 for /dev/block/platform/sdhci-tegra.3/by-name/APP

Patching system image unconditionally...

Watching the CyanogenMod nightly build install onto the tablet

And then, boom, it was back up and running!

CyanogenMod 12.1 Android 5.1.1 home screen

About tablet

The software’s outdated and ancient, but as long as it works as an e-reader and maybe an SSH terminal, I’m good. Fortunately, I have a lot of old APKs backed up, and I was able to drag-and-drop them into Downloads using the Android File Transfer app and then simply open them using the File Manager app.  my archives (not sure how many of these are super useful, I’ll revisit):

• com.adobe.reader.apk  [Adobe Acrobat Reader]
• com.aldiko.android-2.apk [e-reader software, v. 3.0.25; other versions wouldn’t install] (Sad what apparently happened to this app)
• com.amazon.kindle.apk (couldn’t open any books, not compatible...)
• com.anydo_3.4.8.3-2372_minAPI14(nodpi).apk (requires Google frameworks and an account, dropping it)
• com.dataviz.docstogo.apk  [Documents To Go - deleted because it was kinda trash, tbh]
• com.dataviz.docstogoapp.apk  [SSH]
• com.ea.tetrisfree_na.apk  [SSH]
• com.nullsoft.winamp.apk  [Winamp] (ended up not using it, the built in music app is fine)
• com.popzhang.sudoku.apk [Sudoku]
• com.quickoffice.android.apk  [Google Quickoffice 6.5.1.12 circa 2014; pops up messages about no longer being supported, but works to (at least) create documents and save them locally]
• com.realvnc.viewer.android.apk  [RealVNC client] (not installed, wouldn’t install)
• Concise Oxford English Dictionary 11th version.apk  [Concise Oxford English Dictionary - installs then fails trying to download a dictionary]
• jp.ddo.shigadroid.webdavfilemanager.apk  [Easily access WebDAV file shares] 
• Microsoft Office Mobile_15.0.2720.2000.apk  [Mobile version of Microsoft Office, uh, duh...? 🤣]
• org.connectbot.apk  [SSH client]
• org.coolreader.apk  [e-reader software]
• org.ebookdroid.apk  [e-reader software]
• org.mozilla.firefox.apk  [Firefox browser]
• Later installed Firefox-136.0.apk (released in 2025) which is obviously a resource hog on this ancient hardware, but does work (needs Lollipop 5.0 or newer) and makes it a usable, if slow, browsing device)
• org.pocketworkstation.pckeyboard.apk  [Hacker’s Keyboard]
• jackpal.androidterm-1.0.70-71-minAPI4.apk [an Android command line terminal program]
  

Note: To put a password on the device, I had to somewhat counter-intuitively go to Settings, Lock Screen, and then tap where it says “Screen lock (Swipe)” and toggle it from Swipe to either PIN or Password.

Putting a new wallpaper in place was just a matter of long-tapping an empty space on the “desktop.”

Resisting the temptation to accessorize this dead end device, but, lugging it around will make it useful, and a cheap matte BoxWave screen protector will make it desirable to lug around for a while yet...

 

2025.03.18 Update: Added F-Droid for an “open source app store.” Mostly to get VLC going. (I tried loading the .apk and no joy. The version I pulled down through F-Droid works perfectly.) Steps (adapted from this guide):

1. Download isrgrootx1.pem from this guide:
   % curl -O 'https://letsencrypt.org/certs/isrgrootx1.pem.txt'
   % mv isrgrootx1.pem.txt isrgrootx1.pem
2. Copy it to the Download directory on the Nexus using Android File Transfer or OpenMTP.
3. On the tablet: Settings → Security → [Credential storage] Install from storage
   ⋮ → Show internal storage
   ≡ → Internal storage → Download
   Select the isrgrootx1.pem file. The certificate name can be whatever (I used “isrg root”). Credential use: VPN and apps
4. Optional: Verify the root certificate using a non-Firefox browser at https://valid-isrgrootx1.letsencrypt.org/
5. Sideload org.fdroid.fdroid_1015056.apk using Android File Transfer or OpenMTP.
6. Install it via File Manager. Tap “Done” when finished installing.
7. Open the F-Droid app. Wait for it to download repository data. In Settings, Repositories → turn on F-Droid Archive.

2025.03.20 Update: At some point the tablet became unusable, with Trebuchet stopping any time you tried to do anything with it. So I reloaded it from scratch, with an official CyanogenMod boot loader this time. I found this archive of rom images: https://archive.org/details/cyanogenmod-archive

Rebooted holding down all three buttons. Utility menu (Start / Restart bootloader / Recovery mode) on screen.

% ./fastboot devices

015d2109f04c180d fastboot

 % ./fastboot flash recovery ../cyanogenmod-archive/12.1/nightly/recovery/cm-12.1-20161002-NIGHTLY-grouper-recovery.img 

Sending 'recovery' (7818 KB)                       OKAY [  0.949s]

Writing 'recovery'                                 OKAY [  0.997s]

Finished. Total time: 2.065s

Reboot by holding down the 3 buttons; Recovery mode

Boots into Cyanogen Recovery.

On device: Wipe data/factory reset

On device: Install update / via ADB

% ./adb sideload cyanogenmod-archive/12.1/nightly/cm-12.1-20161002-NIGHTLY-grouper.zip

Device: Reboot system now

And when it boots up it will be into a clean install of CyanogenMod 12.1 (Android 5.1.1).

Installed:

1. isrgrootx1.pem certificate and F-Droid (see above)
2. Installed Android Terminal Emulator [jackpal.androidterm-1.0.70-71-minAPI4.apk]
3. Installed Aldiko 3.0.25 [com.aldiko.android.apk]
4. Installed Adobe Acrobat [com.adobe.reader.apk]
5. Installed ConnectBot [org.connectbot.apk]
6. Installed Google Quickoffice [com.quickoffice.android.apk]
7. Installed Hacker's Keyboard [org.pocketworkstation.pckeyboard.apk]
8. Installed WebDAV File Manager [jp.ddo.shigadroid.webdavfilemanager.apk]
9. Installed Firefox 136 [Firefox-136.0.apk]
10. Installed OpenTasks from F-Droid
11. Installed WireGuard [com.wireguard.android-1.0.20231018.apk]