rootfs/usr/local/bin/autorun: adding an explicit check for autorun on new fat32 formatted USER partition

to allow for arbitrary user data.

Containerfile

@@ -184,7 +184,7 @@ COPY --from=util-linux . .
 RUN <<-EOF
     set -eux
     # Increase the size of the ISO by X MB to create space for the third partition
-    dd if=/dev/zero bs=1M count=51 >> airgap.iso
+    dd if=/dev/zero bs=1M count=512 >> airgap.iso
 
     # Append a new partition that uses the additional space
     echo ", +" | sfdisk --append airgap.iso
@@ -196,7 +196,6 @@ RUN <<-EOF
     # This is done by finding the end of the first partition using fdisk, adding 1 sector, 
     # and multiplying by 512 (since each sector is 512 bytes).
     OFFSET=$(fdisk -l airgap.iso | awk '/^airgap.iso1/ {print ($4 + 1) * 512}')
-    echo "Calculated OFFSET: $OFFSET"
 
     # Format the third partition as FAT32 and label it 'USER'
     mformat -v USER -i airgap.iso@@$OFFSET ::