Last year I posted a guide on creating a ESXi 6.7 USB Installer on macOS without any 3rd party tools. This is an updated guide using ESXi 7.0b. I’ve included a short video demonstration. Note, this guide is based on macOS only, if you are using Windows please use the Rufus utility.
Prerequisites
- Download the ESXi Installation ISO (I used ESXi 7.0b)
- A USB Flash Drive Minimum 8GB
Step 1
Open Terminal and list the mounted disks using the diskutil list command.
diskutil list

Step 2
Insert the USB Flash then run the diskutil list command again.
diskutil list
You should now see another disk show up, in my case disk3. Take note for the disk#.

Step 3
Now we need to format the drive with filesystem FAT32 and partition map MBR using the following command. Don’t forget to use the disk# number obtained in step 2.
diskutil eraseDisk MS-DOS "ESXI" MBR disk#

Step 4
Unmount the USB Drive, Note: This is not the same as Eject. Don’t forget to use the disk# number obtained in step 2.
diskutil unmountDisk /dev/disk#
Step 5
Start the command line partitoner fdisk in interactive mode (You will need administrative privileges for this).
sudo fdisk -e /dev/disk#
- Flag the first partition on the volume as active and bootable. “f 1“
- Write the changes. “write“
- Quit fdisk. “quit“
f 1
write
quit

Step 6
Mount the ESXi Installation ISO and copy all the contents from the ISO to the USB flash drive.


Step 7
Locate the file ISOLINUX.CFG on the flash drive and rename it SYSLINUX.CFG file.
Step 8
Edit the SYSLINUX.CFG file with TextEdit, Don’t use a Word program it will mess up the file. Find the line starting with APPEND -c boot.cfg and append -p 1 to it.
APPEND -c boot.cfg -p 1

Save and close the file and eject the USB flash drive.
Step 9
I booted the ESXi installer on my Intel NUC Skull Canyon successfully.

Here’s a Tip! the installer loads the files into memory so you can choose the same USB drive to install ESXi and boot from. Hope you enjoyed this guide.