It is about time I wrote a guide on how to flash back to 100% stock, unrooted. It has been a year since I have been on a stock ROM, so here goes nothing.
DISCLAIMER: I am NOT responsible if you brick or destroy your device performing this procedure. It is to help users and we will help you unbrick if you do brick, but do not be mad if it does not work because you missed a step along the way.
First, back up your data on your tablet. This includes all music, movies, documents, apps, app data, etc. You will need to backup all music, moves, documents and other data outside of apps using a file manager. To backup apps & associated data, I would recommend using MyBackup if you are going back to stock. My favorite is Titanium Backup
but it requires root. If you plan on going to stock rooted, you can use Titanium. If you go to Stock Unrooted, use MyBackup. Store your backups on a microSD, USB, PC or cloud storage. We are going to wipe all the data from the internal memory during this procedure.
Second, assuming you are already rooted, I recommend using TWRP. The easiest way to install it is to download GooManager and install it.
Once you have GooManager installed, open it and grant it SuperUser permission.
Then tap the menu key and choose Install OpenRecoveryScript
Next, tap YES on the popups to confirm the install (should be 2 of them)
The tablet will probably reboot during this process as well.
Next, we want to download the latest Asus firmware for the SKU you want. US=USA, WW=WorldWide, CN=China (no PlayStore), DE=Germany, TB=Belgium, JP=Japan, TW=Taiwan. I would recommend using the US or WW version for most users.
After that file downloads, you will need to unzip it ONE TIME. Do not use a wizard to unzip or it will unzip the file both times. In this case I am going to use Windows to unzip the US_epaduser9_1_27UpdateLauncher.zip and find the file named US_epad-user-126.96.36.199.zip
Using a microSD reader, I will place this file on the top level directory of a microSD card.
Now that we have our new ROM, it is time to boot to recovery. There are some apps and ROMs that can do this for you, but this method works on EVERY TF101 regardless of what ROM, apps, or recovery are installed.
Hold VOL DOWN and POWER for 10-12 seconds until you see some small white text on the screen (Works if you are powered on or powered off):
When you see this text, release both buttons and tap VOL UP within 5 seconds
Next you should see the TWRP logo screen and once it loads, this screen:
Next, it is optional to do a nandroid backup. Go to the Backup section and select what you want to backup, to the internal or external and then perform the backup.
Next, we will wipe the tablet. Back at the main TWRP screen tap Wipe.
I am going to wipe in this order:
Next, we will reboot recovery (Hold VOL DOWN and POWER for 12-15 seconds, release and tap VOL UP.
Now go to the Install section of TWRP
Select the Using external SD radio button.
select the US_epad-user-188.8.131.52.zip file.
Swipe to confirm flash.
When you choose to reboot, it will warn you that there is no OS installed. This is normal, just swipe to reboot.
Run through the setup and off to the races!
Settings screen showing all stock: