NIC shuts off during Windows boot

[LubosD]

I'm trying to get Windows via PXE/iSCSI running on one of my PCs. I've had a lot of success on other PCs, but this one keeps resisting...

I can install Windows 10 just fine on the iSCSI drive, but booting the installed system fails with "inaccessible boot device". That's a pretty common error, but in my case, I can see the network card actually turns off shortly into the boot - which inevitably leads to the failure.

It's an integrated RTL8169SC. Have you ever seen this problem / dealt with it? I can surely install a PXE-capable NIC into a PCIe slot and use that one instead... but I wonder if there's a different solution.