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Table Of Contents
5 (Optional) Modify the boot.cfg file to specify the location of the installation or upgrade script by
using the kernelopt option.
You must use uppercase characters to provide the path of the script, for example,
kernelopt=runweasel ks=cdrom:/KS_CUST.CFG
The installation or upgrade becomes completely automatic, without the need to specify the kickstart
file during the installation or upgrade.
6 Recreate the ISO image using the mkisofs or the genisoimage command.
Command Syntax
mkisofs mkisofs -relaxed-filenames -J -R -o custom_esxi.iso -b
isolinux.bin -c boot.cat -no-emul-boot -boot-load-size 4 -boot-
info-table -eltorito-alt-boot -eltorito-platform efi -b
efiboot.img -no-emul-boot /esxi_cdrom
genisoimage genisoimage -relaxed-filenames -J -R -o custom_esxi.iso -b
isolinux.bin -c boot.cat -no-emul-boot -boot-load-size 4 -boot-
info-table -eltorito-alt-boot -e efiboot.img -no-emul-
boot /esxi_cdrom
You can use this ISO image for regular boot or UEFI secure boot.
The ISO image includes your custom installation or upgrade script.
What to do next
Install ESXi from the ISO image.
PXE Booting the ESXi Installer
You can use the preboot execution environment (PXE) to boot a host. Starting with vSphere 6.0, you can
PXE boot the ESXi installer from a network interface on hosts with legacy BIOS or using UEFI.
ESXi is distributed in an ISO format that is designed to install to flash memory or to a local hard drive. You
can extract the files and boot by using PXE.
PXE uses Dynamic Host Configuration Protocol (DHCP) and Trivial File Transfer Protocol (TFTP) to boot
an operating system over a network.
PXE booting requires some network infrastructure and a machine with a PXE-capable network adapter.
Most machines that can run ESXi have network adapters that can PXE boot.
Note PXE booting with legacy BIOS firmware is possible only over IPv4. PXE booting with UEFI
firmware is possible with either IPv4 or IPv6.
Sample DHCP Configurations
To PXE boot the ESXi installer, the DHCP server must send the address of the TFTP server and the
filename of the initial boot loader to the ESXi host.
VMware ESXi Upgrade
VMware, Inc. 27