Intel Gigabit CT Desktop Adapter (EXPI9301CTBLK)

[robinsmidsrod]

Usually, a bad flash doesn't render a NIC impossible to reflash. It is unusable for network booting, but it most likely works in an operating system, unless the flashed firmware contains some information the hardware needs to perform basic operations (Broadcom NICs come to mind).

I would carefully check that you have the latest firmware downloaded from the manufacturer's website, verify the md5sum of the files to ensure you don't have a corrupted download and follow the documentation to update the firmware. This is not an iPXE issue, as far as I can tell. Good luck!