Add automatic offline update pre condition

Signed-off-by: Sudarshan C Psudarshan.cp2@in.bosch.com

content/guides/ostree.md

@@ -72,16 +72,18 @@ to use it for the system upgrade.
 {{% notice info %}}
 Automatic offline updates will only be triggered when a file with the above
 mentioned special name is found on a USB drive with a single partition.
-Step to check and create partition table on Apertis SDK.
-	$lsblk
-    $sudo fdisk /dev/<drive in which usb is mounted e.g /dev/sdb>
-Enter the below options :
-	p - list the partition
-	d - delete the partition
-	n - create the partition (create single partition with full size)
-	w - write the partition
-Set FAT32 file system type:
-	$sudo mkfs -t vfat /dev/<drive in which usb drive is mounted e.g /dev/sdb1>
+To create a USB disk with a single partition in Apertis:
+- Insert USB device and ensure that it is visible to the Apertis SDK.
+- Use `lsblk` or another tool to determine the disk device file related to the USB device.
+- Create a new partition spanning the USB device (**warning**: this will delete existing data):
+  ```
+  $ echo 'type=83' | sudo sfdisk $DISK
+  ```
+  Where `DISK` is set to the name and location of the disk device file (for example: `/dev/sda`)
+- Format this new partition wit a FAT32 file system:
+  ```
+  $ sudo mkfs -t vfat $DISK
+  ```
 {{% /notice %}}
 
 ### Manual offline update