I bubbled one letter of my name incorrectly but wrote correctly in boxes? (CBSE class 10)
If you have filled your Roll no correctly then according to your number the scanner will match the database and will consider the wrong bubble that you have marked!
Even the Application has another advantage that it either checks the characters or the bubble .Either of them have to be correct
If both of them are wrong ,then there are chances that the paper may be rejected,Else you are good to go