The boot strap seems ureliable ... both F5 and F8b firmware .. both legacy boot and EFI / Windows Boot Manager.
Solution:
Please fix the error ...?
Problem:
Every now and then ... like in 1 out of 10 reboots ... the system (the board) will hang at the Gigabyte splash screen. Especially after Windows Updates. A push on the reset switch triggering a reboot ... may fix this.
BTW
For EFI: Set CSM, do not enable Secure Boot (if you have a Nividia or an AMD gfx ext card), do not enable legacy boot but set EFI Network stack and set UEFI network boot if you use a deployment service. If i.e. WDS on the same subnet - do not use IP-Helpers, but let PXE points to X64 boot image. Clean the disk using diskpart. Now Windows will part the system disk for the OS according to EFI (3 partitions).´Down load hot fix from MS for Win8.1. to remove the watermark stating Secure Boot was incorrectly setup (because Secure Boot basically not supported by many Nividia or AMD gfx cards). Remember, EFI is not something you "enable". It's a spec. working across the system. Most are after the EFI boot explained here.