winpe hangs with sanhook

[robinsmidsrod]

That seems to indicate that your connection is no longer operating at gigabit speed. That is indeed puzzling. I think you should try to capture a packet trace and see what is going on. You might also want to investigate if WinPE operates at gigabit speed when you boot it without the iSCSI volume hooked. It also seems very odd that you have two sessions running for more than 2.5h. One of them should be iPXE and the other should be WinPE. But once WinPE takes over the iPXE one should timeout, because iPXE is no longer able to respond to it. It could be that your IET is not allowing concurrent access to the same volume (which is generally a good thing, because it avoids corruption of the volume), but for this handover to work, you might actually need it. See if there is some form of session limit specified in IET that you can tweak.