[Samsung Galaxy Watch] neuer31:
Hi fellas :)

I got it finally to work, after updating to Android Pie :) :) :)

Time to share how I did it and be aware, I did not test this again in different ways, so there are some uncertainties, I will incorporate them into the places where they belong, so I recommend to first read this guide before doing it, so you are aware of what it requires, what the "risks" are and what restrictions I found so far.

Risks:

No guarantee it works for your devices. I already know from my own testing, it does not work on Android 8.X.

No guarantee this won't damage your phone or something, but that said, I am using this since over 1 year now, no adverse effect or anything :)

Untested if updating of the watch or Tab S4 breaks this - but in my case, I was on the newest version of Android, Tizen, and the needed apps already. That said, sofar updating the watch is not breaking this, after 1 year and several updates.

This is faking the phone's identity to a Galaxy Note 9, this leads to some side effects, ie. in my case the navigations button are stuck on the bottom, pin keypad is only usable horizontally, etc. BUT this is only for the procedure, you can revert after pairing, etc. and it worked ever since for me, even updating the watch software was no problem whatsoever - updating the watch software (the apps on it) you need to do temporary this trick again

Specs of my devices:

Samsung Galaxy Tab S4 LTE (SM-T835)

Android 9.0 - ROOT IS REQUIRED and this will void the warranty of your Galaxy Tab S4, as it is breaking Knox and this is not undoable (afaik)!

Here the exact Android version I use - which is meant for my provider (Swisscom), so please use your appropriate provider version! Only posting if someone is wondering (installed via Odin)

Here the guide which I used to root it (I have also some suggestions that should make it more clear)

Samsung Galaxy Watch LTE 46 mm (SM-R805F)

Tizen 4.0.0.1 (R805FXXU1DSB2/R805FOXA1DSB2/R805FXXU1DSB2 - according to Galaxy Wearable)

IIRC with this new guide you can activate the eSIM normally, in case it does not work:

Activate the eSIM with a known compatible device [but it must have the physical sim card your eSIM is connected to, insert before pairing up ofc.], ie. Galaxy S9, Galaxy S20, Galaxy Note 9 and then connect it with the guide below

Things you need to get this working:

Root (see above)

[Probably] Magisk Module so that Bluetooth connection is not forgotten: "libsecure_storage companion for rooted Samsung devices" (by ianmacd)

Build Prop Editor app (I used this one), hence the root :(

Galaxy Wearable app (tested on version 2.2.24.19031361) - If you download it at the beginning you can find it on the Play Store, otherwise you can find it on apkmirror as well

A file explorer with root capabilities

How to install:

At this point I strongly recommend installing ianmacds "libsecure_storage companion for rooted Samsung devices" in the Magisk Manager app! Otherwise, the tablet will forget the Bluetooth connections! Do not restart as we need to do this in a few moments anyways

Install the Galaxy Wearable app from the Play Store

Open your Build Prop Editor

Change the following stuff to fake your Tab S4 identity (mine is SM-T835, yours might be different) to a Galaxy Note 9 (in this case this specific model SM-N960F) - in the app I suggested you can do that by clicking on the pen top right:

ro.product.model=SM-T835 to ro.product.model=SM-N960F (Note: I could very well imagine this works with another model than the Note 9, as well, I haven't tested it though)

ro.build.characteristics=tablet to ro.build.characteristics=phone

ro.config.tima=1 to ro.config.tima=0 (this is to get Samsung Health app to work, I know this app is refusing to work on rooted phones, maybe other Samsung apps are also affected?)

Save the changes (in the app I suggested there is a save symbol top right) and restart the tablet (to apply)

Yes some of the UI is a bit weird, do not worry, we will revert to the correct identity at the end and everything should be back to normal

Launch the Galaxy Wearable app

Close the app again

Open root file explorer (give it root rights if you have not already done so)

Go to "data/data/com.samsung.android.app.watchmanager/files" and there open rules.xml

Edit the following lines:

Somewhere you will see: <group name="Gear S4" wearable tye [etc]

Below that line are 3 nearly identical line, all like that: <item supportNonSamsung="false" supportTablet="false" pairingImageName[etc]

In any case, all 6 of them (in 1 line there are 2, as there are 3 lines, that makes 6) should be "true"! If that is not the case, change them accordingly

!!! This might have to be redone if the Galaxy Wearable app is updated !!!

Start the Galaxy Wearable app again

Press "Connect to new phone" on your Galaxy Watch (or if it is brand new, then you should be also in the screen it asks to pair up with a new device) - beware: This "resets" your Galaxy Watch (except eSim info), so I suggest to back it up beforehand if you can

In the main menu of the Galaxy Wearable app, you should now see the Galaxy Watch, then click on it

Now it should pair up without any problems and set up properly (at least for me it did work all 4 times :P)

As said, if the mobile network setup fails, you need to setup the eSim beforehand with a known compatible device, as written somewhere above

You can restore a backup from here if you chose to, though you still have to setup some of the stuff again - I tried it without and it still worked without problems

If you have an eSim, check your watch if you have a mobile data connection (go to settings > mobile network > put it on ALWAYS ON just for that test)

Afterwards if you want to use it as a standalone outside your Bluetooth tablet range, I suggest AUTO or ALWAYS ON (beware ALWAYS ON eats a lot of battery, your watch might hold only 12h+ hours) and set in the Galaxy Wearable under "Account and backup", "Remote Connection" to on (which requires the tablet to have a data connection of its own)

Now I suggest to install & update all the necessary apps, see the guide below!

How to update watch apps or install watch apps:

Open your Build Prop Editor [you can skip these first 3 points if you are coming from first install part from above]

Change the following stuff to fake your Tab S4 (mine is SM-T835, yours might be different) identity to a Galaxy Note 9 (in this case this specific model SM-N960F) - in the app, I suggested you can do that by clicking on the pen top right:

ro.product.model=SM-T835 to ro.product.model=SM-N960F (Note: I could very well imagine this works with another model than the Note 9, as well, I haven't tested it though)

ro.build.characteristics=tablet to ro.build.characteristics=phone (this is essential, otherwise, we would need to change some XML file as well)

Save and restart the device

[Resume here if you are coming from the install part above] Open Galaxy Wearable

Open Galaxy Store

Open the 3 lines on the top left, go to Updates and then use the Watch tab

After you have done all the watch app updates & installs

Open your Build Prop Editor

ro.product.model=SM-T835 [SM-T835 is my tablet, yours might be different]

ro.build.characteristics=phone

Save and restart and all should be working as before

Enjoy your fully functional Galaxy Watch with your Galaxy Tab S4!

In case you are FORCED to do an update to the Galaxy Wearable app (it is not recommended to auto-update):

Update like any other app

If everything still works, you don't have to do the following points:

If suddenly it says your device is not compatible or something:

Open root file explorer (give it root rights if you have not already done so)

Go to "data/data/com.samsung.android.app.watchmanager/files" and there open rules.xml

Edit the following lines:

Somewhere you will see: <group name="Gear S4" wearable tye [etc]

Below that line are 3 nearly identical line, all like that: <item supportNonSamsung="false" supportTablet="false" pairingImageName[etc]

In any case, all 6 of them (in 1 line there are 2, as there are 3 lines, that makes 6) should be "true"! If that is not the case, change them accordingly

Save

Start the Galaxy Wearable app again and it should work again

Tested features that work:

Restarting the tablet (on my very first try this triggered some kind of in-app update, but it just repaired and it still works as usual), never had that again later (I repaired/reset the watch several times for testing)

Backup & Restore incl.

Connecting to a Samsung Account (never tested without though, but I see no reason it shouldn't work)

Remote connection (both LTE and Wifi) incl.

Notifications (specifically tested with Gmail and SMS) (both remote and over Bluetooth) and

Calling something (both remote and over Bluetooth)

Automatic Bluetooth reconnect

Widget/App installation & uninstallation (tested with Spotify remote control)

Adding a music track to the watch via Galaxy Wearable and play it

Samsung Health (partially tested, specifically heart rate works)

Calling from the watch, receiving calls to the watch, as standalone or in Tablet range (all 4 are working) (I recommend a Bluetooth headset)

Things that don't work:

Updating / Installing Galaxy Watch apps without doing the guide above

[Sometimes] rules.xml needs to be rechecked after a Galaxy Wearable app [see guide above]

Have fuuuuuuuuuuuun