Which or Android version are you currently on?
There is to reset the Knox fuse on the S9. samsung s9 boot.img
struct boot_img_hdr
If you cannot download a 4GB firmware file, you can extract the boot partition via adb using the command, but this requires temporary root or a custom recovery like TWRP. Without root, you cannot read the raw block device. Which or Android version are you currently on
: Ensure your bootloader is unlocked before attempting to flash any modified images. samsung s9 boot.img