My friends h1 to f1 was also denied. the denial letter said Mr. X has been working on valid H1 visa since X many years so the reinstatement request cant be approved.

after that we did a lot of research cause my friend had a valid job, paystubb and every single documents needed. Later we found that the international advisor requested for reinstatement of f1 status ( reinstating the same old sevis no.). my friend finished his undergrad and worked in h1 for 2 years. Now how can the reinstatement be possible if someone has changed from valid f1 to h1 and now again back to f1? reinstatement is only for those who failed to maintain f1 status by not attaing school the entire semester and bla blah.

In short make sure you apply for renewal of f1 visa (with new sevis id) and not the reinstatement if you have been in f1 and then h1 and now trying back for f1 again. rest of the documents is all crystal clear. good luck