Renaming the ucode file at /lib/firmware/iwlwifi-8000C-22.ucode to fallback to the -21 ucode resolves the issue and wifi begins working normally again.
This is an issue with Linux kernel 4.8 on both yakkety and xenial, so the bug doesn't currently affect users on xenial, but will begin to after the 16.04.2 HWE release. Kernel 4.4 is unaffected because it doesn't attempt to use the -22 ucode
The failure doesn't necessarily affect all machines of a given model with the 8260, but I can reproduce it on multiple laptops when 64GB of RAM are installed (4x16GB). The RAM itself does not appear to be an issue.
The -22 microcode for the intel 8260 wifi adapter has compatibility issues with Linux Kernel 4.8 under certain hardware configurations.
The iwlwifi module crashes resulting in wifi failing with "device not ready" and kernel errors reported in dmesg.
[ 10.691115] iwlwifi 0000:6e:00.0: Microcode SW error detected. Restarting 0x2000000.
Renaming the ucode file at /lib/firmware/ iwlwifi- 8000C-22. ucode to fallback to the -21 ucode resolves the issue and wifi begins working normally again.
This is an issue with Linux kernel 4.8 on both yakkety and xenial, so the bug doesn't currently affect users on xenial, but will begin to after the 16.04.2 HWE release. Kernel 4.4 is unaffected because it doesn't attempt to use the -22 ucode
The failure doesn't necessarily affect all machines of a given model with the 8260, but I can reproduce it on multiple laptops when 64GB of RAM are installed (4x16GB). The RAM itself does not appear to be an issue.