We have been using pxegrub since at least 4.0. This worked fine until 5.1 was released. I never understood what they changed, but at least in theory ESXi should support multiboot.
The following should work, but it never did:
menuentry "ESXi 5.5" {
insmod multiboot2
multiboot (pxe)/esxi5.5-vanilla/tboot.b00
module (pxe)/esxi5.5-vanilla/b.b00
multiboot (pxe)/esxi5.5-vanilla/jumpstrt.gz
module (pxe)/esxi5.5-vanilla/jumpstrt.gz
module (pxe)/esxi5.5-vanilla/useropts.gz
module (pxe)/esxi5.5-vanilla/k.b00
module (pxe)/esxi5.5-vanilla/chardevs.b00
[...]
module (pxe)/esxi5.5-vanilla/imgpayld.tgz
}
We do use a patched grub2 but no Linux or BSD image failed to load, so my guess is, ESXi somewhere violates the protocol. I tried to ask support about this, but we quickly reached the point, where they told me this is not supported. What I still do today is chainloading pxelinux from pxegrub.
menuentry "Chainload pxelinux" {
pxe_restart_tftp /pxelinux.0 10.9.8.1
}
Not the most elegant solution, especially if you have multiple boot images for different hardware. Chainloading might help you with your EFI issues, though. AFAIR, the chainloaded boot loader inherits some of the environment.
If you ever find a way to directly boot from pxegrub2, let me know.
Thorsten
