Stuck iPXE initialising devices - .efi pxe boot

[NiKiZe]

In efi mode normally you have a SNP device available when doing network boot. My guess is that Grub does something with this device, to confirm you could test to boot snponly.efi without grub in between and see if that works, If it does we know for sure that Grub is causing issues in that scenario.

You boot ipxe.efi on different machines from Grub - is it the exact same version of Grub (exact same binary) ? If not maybe they have changed something between version that is causing this issue.

There are some reports now and then about similar hangs from firmware, that happens when iPXE is not allowed to take control over devices, in the case with grub it might be that grub claims something, and refuse to release it and thus iPXE "hangs" forever waiting for it. It would be good if we could narrow down exactly when this happens so issues can be raised on both ends a fix(es) released.

You can boot wimboot from grub, not sure about success tho, there is some posts about it I think.
Another thing to test if it works around the issue is to boot efishell from grub, and then from there boot ipxe.efi.