Hi, I am using iPad 2 with iOS 5. I upgraded server to version 2.2. As MDL-28455 said: „TinyMCE editor upgraded. Safari on iPad/iPhone with iOS5 now works!“ But I still cannot see HTML editor on Safari.
If it is mymobile try to refresh the browser... the button should be on the right side of address bar. For some reason that theme does not seem to render editor even in desktop devices...without refreshing.