How to show 100% health by flashing

 iPhone in 3uTools on the computer

iOS17.4 (and above) block the battery health update. After changing a battery (or core),
 if iPhone shows old battery health, we can get new battery health (100%) by flashing
 iPhone in 3uTools as following steps:
1. Download and install 3uTools at:  www.3u.com 
2. Connect iPhone to computer.    
3. In 3uTools, go to Smart Flash.   
4. Then click Easy Flash.   
5. Choose Quick Flash Mode.  
6. Click Flash. 
7. Tick “Fix battery health during Flash” (This is important to show the new battery health)
8. Start Flash.  

When Flashing completes successfully, iPhone will show 100% at battery health page.