Hi everyone. I encountered this error today and have actually solved it in a strange way, yet I believe it could be helpful for those who do not wish to go down the rabbit hole which is intel tools and drivers.

I have an asus prime z270-a mb which I flashed today. Afterwards I could not connect to the internet. ifconfig showed only my loopback and bridge. I checked dmesg and I got this bad bad message.

[    3.321058] e1000e: Intel(R) PRO/1000 Network Driver - 3.2.6-k
[    3.321059] e1000e: Copyright(c) 1999 - 2015 Intel Corporation.
[    3.330434] e1000e 0000:00:1f.6: Interrupt Throttling Rate (ints/sec) set to dynamic conservative mode
[    3.562634] e1000e 0000:00:1f.6: The NVM Checksum Is Not Valid
[    3.617402] e1000e: probe of 0000:00:1f.6 failed with error -5

So there are many solutions to this which include booting to some tool or customizing the driver to bypass the checksum check.

My solution came when I was curious as to what would happen if I tried to flash the bios over internet. The first bios flash messed it up in the first place. So what would happen? Errors? Complaining? Well it mentioned some reconfiguring and then rebooted; instead of continuing with flashing I decided to check the connection once more. It worked!

tl;dr: Trying to flash BIOS over internet solved NVM checksum issues.