When you request the file from Korg, be specific: "I need the inner storage restore image for Krome 88 (model number KROME-88) for OS version 1.0.2."
Assuming you have legally obtained the korgkromeinnerstorageimage.img file (approx 4.7 GB for Krome, 32 GB for Kronos), you cannot just copy it to a USB stick. You need specific software to write an image. korgkromeinnerstorageimage.img file download