[Samsung Galaxy Watch 3] xxstd:
Update 09/29/20:

1. The latest Samsung Health Monitor Version 1..1.0.175.Caravana (Thanks Caravana for the Mod) Download

This tutorial should work on all Android Phones to enable ECG for your Galaxy Watch 3 and Active 2. BP might also work the same way when it is released in the US.

Basic idea is to create your own certificate to sign ECG.tpk application and install it on your watch, then install the Samsung Health Monitor Mod app on your phone.

I have read lots of threads on XDA and can't find a complete tutorial about how to do it for Galaxy Watch 3 or Active 2. Hope this step-by-step tutorial will help. The whole process took me around 30 mins, it shouldn't be very hard. Make sure you back-up your watch first, just in case anything goes wrong and you need to restore data.

You will need an Android Phone, a Windows PC and Galaxy Watch 3/Active 2 watch for this tutorial. And a wireless network.

Downloads:

1. Download Java for Windows offline (64 bit) https://www.java.com/en/download/manual.jsp and install it.

2. Download JavaSE/Oracle JDK https://www.oracle.com/technetwork/java/javase/downloads/index.html Click "JDK Download" from the top the latest version, then it will direct you to a new page, find "Windows x64 Installer" click the download page from the page and install it.

3. Download Tizen SDK https://developer.tizen.org/development/tizen-studio/download Download Latest Tizen Studio with IDE installer, click "64 Bit" to download and install it.

4. Download ecg.tpk, BP.tpk, Fit2Installer from here(ecg_downloads)

5. Download Samsung Health Monitor Version 1..1.0.167.Caravana (Thanks Caravana for the Mod) from here (See update 09/29/20 from the top of the thread to download the latest version)

On Your Phone:

1. Install Samsung Health Monitor Version 1..1.0.167.Caravana on your phone. Open the app enter your name, BOD and etc to finish the setup.

On Your Watch:

1. From your watch, Go to "Settings"->"About Watch"->"Software"->Click On "Software Versio" 5 times until it shows "Developer mode turned on"

2. Go back to "About Watch", make sure it shows "Debugging is turned on", it not click "Debugging" and turn it on.

3. Go to Wifi settings on the watch, change wifi setting to always On, and connect it to the same wireless network with your PC.

4. Reboot the watch. Make sure wifi is connected after the reboot.

From Your PC:

1. Launch Tizen Package Manager and Navigate to 5.5 wearable(It depends on your watch's software version, eg mine shows Tizen Version 5.5.0.1, so I navigate to 5.5 wearable), then click Install icon

2. Scroll down to the Tizen SDK tool and click the install icon

3. Click on the Extension SDK tab

3.1 Click the arrow on Extras

3.2 Install Samsung Certificate Extension and Samsung Wearable Extension

4. Check the Progress tab, once it shows 100%, you can close Tizen Package Manger and do not launch Tizen Studio(we don't need to use Tizen Studio)

5. Open up "Certificate Manager"

6. Click on the "+" icon and from the pop-up window click Samsung Logo.

6.1 Device Type -> Mobile/Wearable, Click Next

6.2 Certificate Profile(Give it whatever name you like), Click Next

6.3 Author Certificate -> Create a new author certificate, Click Next

6.4 Author Certificate -> Enter Author name, Password, Confirm Password as required(Remember the password,. you will need it when you sign the TPK file) and click next

6.5 A pop up will ask you to sign in to your Samsung account, enter your account information and sign in

6.6 Now it will show your certificate has been saved at C:/Users/USERNAME/SamsungCertificate/cert_name and click next.

6.7 Create a new distributor certificate and click next

6.8 Do not change Privilege and password information, do not close these windows, just leave it there, we need to enable debug mode from the watch and connect it to PC now.

7. Open Tizen "Device Manager" from the PC.

8. Click the "Remote Device Manager" icon from top right corner.

9. From pop-up windows, click the "Scan Devices" icon from the top right corner.

10. Once it find your watch turn the connection switch to on. and close pop-up windows. At this time, you should able to see lots of debugging information from Device Manager. (If you don't see debug information, try these steps: 1. Turn off your windows firewall 2. turn off bluetooth&GPS on your watch 3. reboot your watch )

11. Go back to Tizen Certificate Manager, step 9.8, we can see one DUID has been added automatically. Click next.

12. It will show your certificate has been saved at C:/Users/USERNAME/SamsungCertificate/cert_name, Click Finish.

13. Download Fit2installer.zip unzip the whole folder to your desktop.

14. Go to the certificate(C:/Users/USERNAME/SamsungCertificate/cert_name) you just created and copy all files. inside the folder

15. Go to C:\Users\USERNAME\Desktop\Fit2Installer\cert Paste all the certificate file you just copied.

16. Copy ecg.tpk file and paste it at C:\Users\USERNAME\Desktop\Fit2Installer\sign_me

17. Click sign.bat from the Fit2Installer folder. Enter your certificate password.

18. It will show "Package( C:\Users\USERNAME\Desktop\Fit2Installer\install_me\ecg.tpk ) is created successfully." and enter any key to close the window.

19. Now go to "Device Manager", right-click your device, choose "install app", Select ecg.tpk file from C:\Users\USERNAME\Desktop\Fit2Installer\install_me.

20. Wait a few seconds, you should see ECG app has been installed on your watch. Open it.

21. Open the "Samsung Health Monitor" app from your phone, you should be able to read the ECG data from your watch now.

As Blood Pressure has not been released in the U.S, once it released, you should be able to activate for Non-Samsung phone the same way. You can disable debug mode if you want now.

Enjoy!

Reference:

1. https://xdaforums.com/showpost.php?p=83574519&postcount=6

2. https://www.reddit.com/r/GearS3/comments/aljplu/tutorial_how_to_install_tpks_and_wgts_onto_your/

3. https://xdaforums.com/smartwatch/gear-fit/howto-sign-sideload-tizen-applications-t3639793