ECG – Electrocardiogram, also known as electrocardiogram, is now locked on Apple Watch and you only use it in some countries. In Vietnam, of course, you can't use it even if you're using Apple Watch (Series 4 or Series 5) of the US (LL / A). I have found a solution that helps us activate ECG right here in Vietnam and I have succeeded, and please share it again for you.
First, download the iMazing application on the Mac computer at the link HERE (Link of maclife.vn)
Make sure you are using Apple Watch Series 4 and Series 5. And unpair your Apple Watch with iPhone.
Initially plugging the cable connected to the Mac, open the app and select Backup. Remember to Enable Backup Encryption (as above).
Backup finished, select the Backups (as shown above), then select the backup file (with the key) below and select Edit.
Now you look at the left column is the "Editable Backup" of your newly created, you choose to File System – Choose HomeDomain
From HomeDomain, choose one at a time Thư viện then select Preferences
Now, download the PLIST file at the link HERE – Remember to click Download Zip to download!
The PLIST file has the format: com.apple.private.health.heart-rhythm.plist
From Preferences, right click and select Copy to "Preferences" – then you put the new file PLIST downloaded above.
So it was successful, you choose to file Editable Backups – then select Restore to Devices to restore this entire iCloud backup file to your iPhone again
Before restoring, it will ask you like this, remember NOT to check the Erase Target Device (s) box. Because if you tick, you will lose eSIM data (if you use an iPhone with eSIM).
Note: if the restore process is reported full iPhone capacity, it is best to delete photos, videos that you feel redundant.
It is done! Use that iPhone to pair with the Apple Watch, and remember to select "Set up as new Apple Watch" and not "Restore from backup"!
Enjoy ECG, I wish you success!
Additional note: If there is still no ECG go unpair with the iPhone and then pair from the beginning.