[Thinkpad Tablet General] JonW434:
It has been some years since I did any Android stuff, so all of this is a bit like learning it from scratch all over again.

If anyone else reading this thread and doesn't know very much, I've provided some links that helped me, in order to refresh my Android memory or learn some things that have changed since then.

How to pass SafetyNet on Android after rooting or installing a custom ROM

It is possible to pass SafetyNet, even after extensive modding like rooting or installing a custom ROM. Check out how to do that here!

www.xda-developers.com

I didn't realise that SafetyNet authentication is broken, even when using stock rom, as soon as bootloader is unlocked. I thought it was only when using a custom ROM or getting root access. I assume that no one has been able to get SafetyNet pass on this device so far. And it gives a very big reason for wanting root access in order to overcome this, if wanting to use banking apps etc. In terms of trying one of those 5 different methods.

How A/B Partitions and Seamless Updates Affect Custom Development on XDA

You may have heard of Seamless Updates before. It involves something called "A/B partitions." What is it and how does it affect custom development on XDA?

www.xda-developers.com

There has been talk of A/B Partitioning for Seamless Updates, and I know almost nothing about this, I've only started seeing it talked about in the last few days, so I'm sharing that link for anyone else who needs some context. I know that most here already know this basic stuff, but posting as a point of reference.

Fun with GSIs: A Retrospective on Project Treble’s Impact on Custom ROMs

Project Treble not only significantly changed Android's architecture, but it also ushered in a new era of custom ROMs thanks to GSIs.

blog.esper.io

This is an excellent overview of GSI showing the history of GSI and where the whole idea came from, and the implications of using it. He has many extra links showing extra information for any given subject. And the writer of the article even has a Lenovo tablet and installs a few.

Generic System Image (GSI) list

Notes about tinkering with Android Project Treble. Contribute to phhusson/treble_experimentations development by creating an account on GitHub.

github.com

A list of GSIs..

Goals

- an easy guide to make SafetyNet pass on this device, doing it manually via root access. Similar to the excellent GitHub GSI install guide posted by dcn1961.

- or finding a way to do it on one device and then adapt it into a custom rom, so that it can be automated into the install, with no root access is required. I've done this kind of thing on Windows before, but on Android I know very little about this, only that others seem to be able to do it for other phones or tablets. It would require a very advanced user. It may never happen on this model of tablet, but just saying.. it would be a nice thing to aim for in the long term.

- figuring out why the face lock thing prevents installation for some GSI roms but not for others. And what can be done to fix it.

- Widevine L1 doesn't seem possible on most unlocked Android devices. That means HD video for streaming will always be compromised. I've seen it possible with some Oneplus devices, but it needed some cooperation from the official sources of the firmware in order to work. It's a rare thing in order to unlock this and likely won't ever be possible for this device.

Therefore, it would seem that stock configuration might be the preferred option. But even with that, there seems to be a problem for some users running 100% stock, the Lenovo OTA updates can fail and won't complete to 100%, looping the update and it can never complete. Rescue with SMA fixes it, but isn't ideal in terms of having to factory reset and use restore backup all of the time. I haven't been able to find info on why this is happening for some users and not others. Either way, it's interesting to see what the possibilities there are one way or the other. For learning purposes etc.