With the 7.2 experience update most users had no problems at all.The thing is that some reported minor issues, hickups or apps that are no longer compatible in the Playstore.More and more however now report serious issues from the remote and controller making big problems ,over to general sound or BT pairing problems and all the way to soft bricked devices.

Be aware that those really serious problems only affect the users with a rooted developer rm or a developer rom that has at least the bootloader unlocked!
All Shields running on the stock firmware, which is not rooted and fully genuine for this reason, will have no real dramas with the 7.2 update!
The OTA will work just fine here and all issues that can come up are already being worked on by the Nvidia developers - which I think shows superior support!

I started my Shield life on a 16GB model from 2017 and the first thing to do after the initial setup was to switch to the developer firmware as I like to mod my Androids a bit and also like ad blockers.Had no issues at all with updates, changes or such things - until the 7.2 update showed up in my notifications.But before I go into details of my fixes for the developer update I would like to list some of the most reported issues first.

A very common problem after the update is that remote and controller seem to be lost for the system.Patience is the key after the first reboot as the system still does a lot of things in the background.The remote should start to work again as normal after 5 to 10 minutes, a bit longer if you still have active updates downloading through the playstore.Really bad problems only happen if you reboot before all the background tasks are finnished.

BT devices get re-assinged and also get new priorites with the 7.2 update.Sound bars or other paired BT devices seem to be no longer properly pairing or fail to work at all.Sadly the only way to prevent this that I found requires to disconnect all connected devices except the remote and controller.So all drives gone, all servers stopped.Hard drives are worse off than SD cards in a reader or USB sticks.If left connected thier internal name for the system might be altered.This causes databases on there, like used by Kodi or Plex to fail as they no longer find the information source they have linked.

The most severe issue however is that the OTA is not garanteed to actually give you the right update file!I had several fails on the stock firmware for no obvious reason while some updates succeeded.All failed attempts resulted in the progress bar after the reboot to stop at the 1/4 mark instead of slowly moving on.For developer firmware this is especially bad as there is a 70/30 chance you get the 422mb stock update instead of the 1.1Gb developer update.

As said, I prefer the developer firmware, so now two ways to make the update work first:a) Flash the unmodified developer bootloader after removing all rooting related stuff and added things on the system partition.Lock the bootloader.Let the update do its thing and hope you get the right file.b) Sideload the copied 7.2 update through ADB.In this case the bootloader of the recovery is used instead of calling te recovery from a potentially modifed or patched bootloader.Which means all things that might have been tempered with will be ignored and written over if original files are present in the update.

Both of the above ways to overcome the failure of the OTA update mean that a full root is no longer possible!Although the developer firmware should come pre-rooted, meaning only superuser and busybox are required, it fials badly.No matter what I tried the system is flagged as corrupted and no longer trustworthy.Using Magisk fails even worse as the patched bootloader causes a bootlooop.Due to the modifications in the bootloader that the 7.2 update made TWRP also fails.It seems 7.2 was also intended to end full root support, unintentionally maybe, still bad.A rollback to the 7.1 bootloader without massive mods in some system files and risking some apps not fully working with the newly advertised features is impossible too.The kernel is still the same, so it is added or gone wrong security functions in system and bootloader.As a last attempt I used the already patched 7.1 bootloader with the right checksum to manually apply the boot.img.p patch of 7.2.Magisk confirmed the image is patched and fine, installing it still caused a total failure until the 7.2 stock bootloader was installed again.

Tested and working rollback options to 7.1:If your update went through the first reboot and actually made it to the end of the progress bar then please do not bother.In your case a full backup of all apps, settings and data would be required before you need to flash the 7.1 and literally loose all that has no backup.But in cast the update never makes it through and after a reboot you are prompted for the update again it is very easy:Dismiss the update!If the download already started, pause it by going into the settings, about, update or what it is called.On the screen that pops up you can then pause the download.Clicking on the notification should work too in most cases.In this case your Shield downloads the wrong update and realised it before actually changing any files at all.The last case I can offer a fix for is possible if your update started fine but then after the reboot stops at around 1/4 on the progress bar.If after 15 minutes or so it still won't move and a reboot only gets you back to that point directly it is fixable.Same if you gave it plenty of time (like an hour) and and after you force a reboot it ends in a loop or the dead droid on its back.The solution is to download the 7.1 recovery firmware from Nvidia.In the "flash-all.bat" file add :: and a space to the beginning of the line containg the command to flash te system partition.Or just delete the line.Save the file and then call the flash-all batch file in the command window.Detailed instructions for ADB and fastboot can be found together with the downloads for the recovery image of the developer firmware.If in doubt head over to CDA developers and download simple ADB after reading the basic instructions.Installing the 7.1 firmware without the system partition will give you the state of your Shield as it was before the update messed it all up.All partitions, except the system will be replaced by the original 7.1 ones.And since the update failed before reaching your system partition, leaving it out from the firmware install means you get all back working fine again.Then just dismiss the update as it will be back right away.

I can upload the correct 1.1Gb 7.2 developer update for those not requiring a fully rooted device.For the stock update I can only try to get the files for the 16Gb 2017 model as I only have this one.

Update:Nividia support confirmed that they fixed the issue with the developer firmware update by now permanently changing it to the full update.The 422mb file was indeed the correct one for the developer firmware but the block based update fails under certain conditions.I uploaded the 7.2 developer firmware update here: https://drive.google.com/file/d/1sQSIrf5P8Ea9IDKCE-tPKF-ropDonqJ3/view?usp=sharing

It should not be required anymore if you now see a 1.1Gb download.Please note: this is the developer firmware and not suited to update a Shield that was using the stock firmware!You need to sideload the update through the recovery and ADB!Support also indicated that for the majority of users the update works just fine on both types of irmware as well as on the older models.Only modifications to the system partition, recovery, bootloader (like unlocking) or kernel will cause a total failure.And in that case, if you get the screen with the curruption and trust issues the above update will fix it is applied manually - again only for the developer firmware.From what I can see the worst that would happen on a stock firmware is that you end up with the developer firmware but I did not bother to confirm on my device.The normal issues related to the successful install of the update are addressed by the support as well but for obvious reasons it it best if you open a support ticket with the Nvidia support and give all the details you can find about the problem and hardware/apps involved!