How watch device diagnostic free by mfc software ?
How is work ?
A, Connect device into DFU mode and connect to mfc software via iBUS (Cable can be lightning USB or DCSD)
B, Once device connected to software , go to Diag tab press "Load Diag" button and waiting for the diagnostic process to complete automatically
C, If Step B Operation finished, Press "Connect" button, then you can choose read & Write function as needed (If Exploit Failed, need Repeat the all the steps again including reput device into DFU)
D, E.G. Watch S3, After you changed the Serial Number, BT And Wifi Data (Usually Can Use A7 Or A8 Data), You maybe need manually reset the Watch, Then You will be able to pair with your Phone.