The first volume of Maktubat sharif contains 313 letters with three additional letters appended at the end which were written by his son Khwaja Muhammad Sadiq Faruqi Naqshbandi (who died at a young age of 25).
Digitized by the University of Kashmir
A low quality version (150 dpi) can be downloaded below. There are 416 pages in total, weighing about 1.45 GB as raw pictures. Original pictures are available at http://18.104.22.168:88/Manuscripts/
Files hosted at archive.org