This error usually indicates an unrecognised image format or, less commonly, a corrupted image.

Things to try:

• Check that your build of iPXE supports the type of image you are trying to boot. You can see the list of supported image types in the iPXE start-up banner; for example:

      iPXE 1.0.0+ -- Open Source Network Boot Firmware -- http://ipxe.org
      Features: HTTP iSCSI DNS TFTP AoE VLAN bzImage COMBOOT ELF MBOOT PXE PXEXT

  shows that bzImage, COMBOOT, ELF, Multiboot, and PXE images are supported in this build of iPXE.

• If you are running a UEFI version of iPXE then only EFI binaries can be loaded. PXE binaries such as pxelinux.0 and memdisk use legacy BIOS calls and can never work on UEFI.
  • If you are trying to load a Linux kernel (or other EFI binary) then you can use iPXE to load it directly; there is no need to load pxelinux.0 first.
  • If you are trying to load a Linux kernel, make sure it is built with CONFIG_EFI_STUB enabled. Most distribution kernels will already be built with CONFIG_EFI_STUB enabled.
  • If you are trying to display a pxelinux menu then you may want to investigate iPXE's native menuing capabilities.

• Check that the image you are trying to boot has not been corrupted in any way.
  • You can use the imgstat command to check that the filesize is correct and that the file has been detected as the correct type.

• If you are trying to boot an iPXE script, check that the “#!ipxe” signature is present at the beginning of the script.
  • If you have edited the script on a Windows machine, check that the script was saved using ASCII (or UTF-8) rather than UTF-16 encoding, and that your Windows editor has not inserted a byte order mark (BOM) at the start of the file.