Working with VMware can be simple or difficult, it depends on what you are trying to do. Something simple would be installing VMware ESXi 4.1 from CD to the local hard drive, something complex would be installing VMware ESXi 4.1 from USB flash drive to internal flash media is a bit tricky. And since you found this post I am willing to bet that you are now getting the mboot.c32 not found error. Well lets solve that one first.

To resolve the mboot.c32 not found issue you are using too new of a version of unetbootin you need to use unetbootin 4.9.4 this will solve that issue and allow the installer to boot from USB. The same methods apply, I am not going to post screen shots, just click the ISO option and browse to your downloaded ISO the create.

After you have it on USB you can now boot from it, but it won’t install, go ahead, try it. You will get an error of

Unable to find the system image to install. 
This is due to the image not being mounted correctly or the CD-ROM not
being supported. 

Well at this point the simple way to solve it would be to throw the USB stick out and go find an external DVD drive, but really what fun would that be.

The next thing that is needed is this replacement for ienviron.vgz located on Eric Sloof’s blog.

Once you have that, delete the ienviron.vgz from your USB stick and put this one there. It mainly has changes to the partition sizes so that it can install to a USB.

Ok so now that you have both these items in place, how to use them easily, well lets make a kickstart file.

Create a file on the USB drive and call it ks.cfg then edit it with notepad. Mine is here

   1:  vmaccepteula

   2:  rootpw changemetosomethingthatyouwoulduseandisshorterforconvenence

   3:  autopart --disk=mpx.vmhba32:C0:T0:L0 --overwritevmfs 

   4:  install usb 

   5:  network --bootproto=dhcp --device=vmnic0 

Milage may vary on the script, make sure that mpx.vmhba32:C0:T0:L0 is your internal flash memory or it will overwrite your USB drive

Now to the config file, you need to modify the syslinux.cfg file and add ks=usb to line 8,

   1:  default menu.c32

   2:  menu title VMware VMvisor Boot Menu

   3:  timeout 80

   4:   

   5:  label ESXi Installer

   6:  menu label ^ESXi Installer

   7:  kernel mboot.c32

   8:  append vmkboot.gz ks=usb --- vmkernel.gz --- sys.vgz --- cim.vgz --- ienviron.vgz --- install.vgz --- mod.tgz

   9:   

  10:  label ^Boot from local disk

  11:  menu label ^Boot from local disk

  12:  localboot 0x80

Once that is complete, plug the USB drive into your new VMware host and it will automagicly install to the internal flash and then just tell you to press enter to reboot. That’s it.