Comment 2 for bug 2042716

That error in itself is not problematic. The kernel walks down until it finds an (older) FW to load, in our case that's -81. However, there are lots of kernel traces in the log related to wifi which could be due to old(er) FW.

Can you download the latest FW from here:
https://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git/plain/iwlwifi-so-a0-hr-b0-83.ucode
put it in /lib/firmware, reboot and check that it is loaded and verify if wifi is working now? And please attached the kernel log from that boot/run.