Linux

1. Open a terminal and create a staging directory:

   mkdir ~/USBEFR_STAGING
   cd ~/USBEFR_STAGING

2. Copy the downloaded EFR image to the staging directory.
3. Verify the SHA-256 checksum of the EFR image:

   sha256sum <EFR_IMAGE_FILE.img.gz>

   Compare the output against the checksum from the Customer Support Portal.
4. Extract the compressed EFR image:

   gunzip <EFR_IMAGE_FILE.img.gz>

   This produces an uncompressed file: <EFR_IMAGE_FILE.img> (approximately 8 GB).
5. Connect the USB flash drive to your Linux computer.
6. Identify the USB drive device path:

   lsblk -S -o NAME,TYPE,VENDOR,MODEL,SIZE,TRAN

   Identify your USB drive by its size and note the device name (for example, /dev/sda).
7. Unmount any partitions on the USB drive that are automatically mounted:

   sudo umount /dev/sdX*

   Replace sdX with your device name.
8. Write the EFR image to the USB drive:

   The dd command will overwrite all data on the target USB drive. Double-check the device identifier before running the command. Targeting the wrong device can permanently overwrite your file system.

   sudo dd if=<EFR_IMAGE_FILE.img> of=/dev/sdX bs=4M status=progress conv=fdatasync

   Replace sdX with your device name. The operation completes when dd displays a summary of records transferred.
9. Verify the USB drive file structure by mounting it and listing its contents:

   sudo mkdir -p /mnt/usbefr
   sudo mount -L USBEFR /mnt/usbefr
   ls -R /mnt/usbefr

   The USB drive should contain the following directory structure:

   EFI/
     BOOT/
       BOOTX64.EFI
       grubx64.efi
     centos/
       SHIMX64.EFI
       grubx64.efi
     fonts/
       unicode.pf2
   boot/
     resusys.vmlinuz
     resusys.cpio
     resusys.cpio.sig
   IMAGES/
     README