fixed:

xorriso
 zscaler
 first_install
 hostname
added:
  qemu script
  timzone
  realname
disabled systemd-networkd-wait-online

build-iso.sh

@@ -138,17 +138,21 @@ GRUBENTRY
   mv "$WORK_DIR/grub_merged.cfg" "$GRUB_CFG"
 fi
 
+EFI_LINE=$(fdisk -l "$UBUNTU_ISO" | grep "EFI System")
+EFI_START=$(echo "$EFI_LINE" | awk '{print $(NF-5)}')
+EFI_END=$(echo "$EFI_LINE" | awk '{print $(NF-4)}')
+EFI_COUNT=$((EFI_END - EFI_START + 1))
+
 # ── Repack ISO ─────────────────────────────────────────────────────────────────
-info "Repacking ISO → $OUTPUT_ISO ..."
 xorriso -as mkisofs \
   -r -V "Ubuntu-AutoInstall" -o "$OUTPUT_ISO" \
   -J -joliet-long \
-  --grub2-mbr "$WORK_DIR/mbr_template.bin" \
+  --grub2-mbr --interval:local_fs:0s-15s:zero_mbrpt,zero_gpt:"$UBUNTU_ISO" \
   --protective-msdos-label \
   -partition_offset 16 \
   --mbr-force-bootable \
   -append_partition 2 28732ac11ff8d211ba4b00a0c93ec93b \
-  --interval:local_fs:1s-300s::"$UBUNTU_ISO" \
+  --interval:local_fs:${EFI_START}d-${EFI_END}d::"$UBUNTU_ISO" \
   -appended_part_as_gpt \
   -iso_mbr_part_type a2a0d0ebe5b9334487c068b6b72699c7 \
   -c '/boot.catalog' \
@@ -156,8 +160,9 @@ xorriso -as mkisofs \
   -no-emul-boot -boot-load-size 4 -boot-info-table \
   --grub2-boot-info \
   -eltorito-alt-boot \
-  -e '--interval:appended_partition_2:::' \
+  -e "--interval:appended_partition_2_start_${EFI_START}s_size_${EFI_COUNT}d:all::" \
   -no-emul-boot \
+  -boot-load-size $EFI_COUNT \
   "$WORK_DIR/iso"
 
 info "Done! ✓"