For anyone, any color, any age, any whatever...it is always best to learn the basics first.
Repeating a year in high school is much better than a social promotion. Learning the subject is much more important.
( We both know this, but lurkers here may not )
Repeating a year in elementary school is even better, if the student can read and add at the end of the second year. (Ideally, they'd have learned the first year ...)
Our local school districts are trying to bring up high school test scores, especially for minorities, but there's only so much you can do with teenagers who can't read well. They've got to put the effort into basic literacy and math.