How to use ECG & Blood Pressure on a Galaxy Watch 4 without a Samsung Phone using a modded Samsung Health Monitor App

My initial impressions of the Samsung Galaxy Watch4 have not started well. When I first set up the watch it because apparent that the ECG and blood pressure function would not work on my OnePlus Nord 2.

It turns out some functionality is walled off for users with a Samsung phone. While this may be common knowledge, it is something I was not aware of.

Looking at the official Samsung Galaxy Watch4 page, they have hidden this under the disclaimers section part 3. Obviously, it is my fault for not reading the disclaimers, but like most people don’t read terms and conditions, it was an easy thing to miss, and I am sure that many buyers will do the same. It feels very misleading.

It turns out that it is possible to get this functionality working on other phones using a modded Samsung Health Monitor app. This is great news for me, allowing me to enjoy the watch to its full potential, but it also shows that Samsung is being quite underhanded by limiting this functionality to their own phones.

This guide is almost a carbon copy of the instructions provided by Dante63 at XDA Developers, so if this guide is useful to you, please go over there and thank him.

Download the Modded Samsung Health Monitor App files

You will need:

• Minimal ADB Fastboot where is available here
• The modded Samsung Health Monitor App which is in the same folder as Fastboot – there is also a folder providing instructions in multiple languages
• The modded Samsung Health Monitor App that you will need to send to your phone. This is in the root of the main SMH WearOS folder uploaded by the XDA team here

Install the Samsung Health Monitor App on your Android phone

I uninstalled the official Samsung Health Monitor App before installing the modded version. I don’t think you need to do this anymore, but there is no point having two versions running anyway.

At the time of writing, the APK file name you need to install is : Phone.WearOS.MinSDK24-SHM1.1.1.153.root.detection.country.restriction.removed.dante63.apk

I downloaded the files to my PC, so I normally send myself APK files via Telegram and install it from there. It is probably faster to go to the Google drive and download the file directly, though.

Enable Developer Options & ADB Debugging on Samsung Galaxy Watch4

1. Disconnect the Bluetooth (optional) and connect the watch to the same network of your PC/Laptop.
2. Go to config -> about -> tap the software version until it says “Developer mode turned on”…
3. Go back to the config menu and you should see developer options above the about, tap it…
4. Enable ADB Debugging and ADB Wi-Fi, write down the IP that you see under ADB Wi-Fi
   1. If you don’t see an IP you can go to settings > connections > Wi-Fi and click on the network you are connected to, you can then scroll down and see the IP

How to install the modded Samsung Health Monitor on your Galaxy Watch4

This is where things get a little more technical. With Windows, I find using PowerShell is easier.

You will need to unzip Fastboot into a folder. Then place the Watch4.SHM.MOD.1.1.0.171.apk within that folder (the file name may be different if a new version have been released when you read this)

Then press shift and right-click on any white space within the folder. This will show the context menu and you have an option to “Open PowerShell window here”

The above screenshot has all the steps I did.

With PowerShell, when you run a command, it needs to have .\ in front of it.

1. start the ADB Server by killing it first to be safe no adb instance is running:
.\adb kill-server
then type:
.\adb start-server

Results:
* daemon not running; starting now at tcp : port
* daemon started successfully

2. Connect to the watch, replace IP with the number you got from the Watch4, type:
.\adb connect 192.168.1.121 (this seems to be the IP the watch defaults to if you have a 192.168.1.* network, on my network, I had a CCTV camera at that IP, which caused issues, so you may need to manually assign an IP if you have problems, I temporarily unplugged my camera)

On your watch, allow the connection from the computer…
Results:
connected to IP : PORT

3. OPTIONAL STEP: if you have the original SHM and want to uninstall it, do the following:
.\adb shell
then type
.\pm uninstall -k –user 0 com.samsung.android.shealthmonitor
finally type:
.\exit

4. Install MOD SHM, type (Replace the X with the version or simply make sure you put the name of the apk you are installing to the watch if you will rename the apk):
.\adb -s IP install Watch4.SHM.MOD.1.1.0.171.apk

The modded Samsung Health Monitor app you installed will have a little M in the upper right corner to differentiate it from the original Samsung Health Monitor app. From this app you can do your ECG and blood pressure. The blood pressure functionality needs to be calibrated with you taking your own blood pressure using a cuff based blood pressure machine.