Korg does officially provide the full internal storage image on their support site; they only offer the KROME System Updater for functional keyboards.
Korg distributes the OS update ( .upd files) publicly. The Inner Storage Image is technically a service tool file. This leads to many dangerous "sketchy" download links on Google Drive and Mediafire. Korg Krome Inner Storage Image.img File Download -BEST
Open the Krome chassis (requires careful disassembly) and swap the old internal card for the new one. Korg does officially provide the full internal storage