Windows iSCSI - chain bootx64.efi?

[misty]

For installing and then booting Windows from SAN (iSCSI Target) I am using two distinct stages -
* Stage 1 - SANHOOK target and boot WinPE - then run the installer
* Stage 2 - SANBOOT target and complete the installation.

For Stage 1 I have previously used wimboot to load WinPE. On BIOS systems I have more recently started chain-loading pxeboot.0 instead. This works well on BIOS systems.

Attempting to do something similar on UEFI systems (using a snp build), this time chaining bootx64.efi, fails. Error is 0x7b (inaccessible boot device). Avoiding the use of iPXE and using bootx64.efi as my network boot file works fine in loading WinPE.

Can Windows bootx64.efi be loaded/chain-loaded successfully from iPXE? If yes, how?

Regards,

Misty