Booting Linux using UEFI can brick Samsung laptops
Booting Linux using UEFI just once on various Samsung laptops is enough to permanently stop them working. Several reports have been posted on the Ubuntu bug tracker, but the problem is likely to also be present in other Linux distributions, as it appears to be caused by a kernel driver for Samsung laptops. Kernel developers are currently discussing a change which would disable the driver when booting via UEFI.
You don't need to be a genius to debug a pf.conf firewall ruleset, you just need the guts to run tcpdump