Good day. Thank you for the question.
The SMS command for updating Odometer reading will be as follows:
With login and password: login<space>password<space>setparam 1285 X
Without login and password: <space><space>setparam 1285 X
Where X is the odometer value.
Alternatively, you may also go through this link file:///C:/Users/User/Downloads/FM1100%20User%20Manual%20v5.17.pdf.
Please try this out and let me know if it helps.