I used the Gigabyte Z97X-UD5H-BK. All Links are in the Sources-Section at the bottom of the page.
NOTICE: You need to use a modified version of a offical tool. If you are not comfortable with that, leave.
I had a pretty good mainboard from Gigabyte in storage. I used it for years, but it had one really really BIG problem. When something in regards to boot devices changes (USB with Linux / Windows on it or even installing a new hard drive / SSD) it freezes on startup on at the Gigabyte Logo. But it is not like an Operating system issue or BIOS-Settings issue. It is actually suck and does absolutely nothing even after removing everything! No key works. Even resetting CMOS or removing the battery didn't fix it. For some reason after 20 or more resets and reboot it worked again. And now the biggest WTF: the boot selection / boot order remembers everything ever on the drives! Stuff like OpenSuse, the windows bootloader or some random entry named UEFI-OS never disappeared even when everything disconnected. EVEN AFTER CMOS RESET AND THE BATTERY REMOVED FOR AROUND 2 YEARS! It themes like the BIOS is saving that Stuff on one of the chip's.
After years I tried again to fix it and I did it! But it was not easy. First, I needed to make a CMOS-Reset button smash party until it booted. I prepared a USB-Stick with FreeDOS on it. Use Rufus and select the integrated FreeDOS! This is important. Now you need to downgrade the bios as far as possible with the installed hardware/CPU. I downgrade from F8 to F5 (F5 was the first BIOS that supported my CPU). The issue is that officially Gigabyte dose not allow you to do that. But lordkag over at winraid.level1techs.com made a HEX-Modded version of the official Gigabyte-DOS-BIOS-Flasher (yes that exists) and it can downgrade your BIOS! But more importantly: It can clear the bios chip completely which fixes the BOOT LOGO freeze! I needed the newest Version possible (at the time of writing "Efiflash modified v0.80.zip"). Older versions just complained about the image being outdated like the Integerded Bios flasher itself would do. After that, everything worked perfectly!
Pro-Tipp: I noticed that many people online use this mainboard for 🍏 installations. I can imagine that this could be one of the causes of the issue. It also could be that the F8 firmware itself is just buggy. I downgrade to F5 and updated to F6 for better overclocking support. If you what to know how far I could push my CPU on this mainboard read this:
twitter.com - My post about the overclock. (Did not think it is worth a hole Blog entry. Every CPU is different!)