I have an Elgato Thunderbolt 2 dock that usually works flawlessly with my MBP. I’ve got all kinds of stuff hooked up to it: screens, USB peripherals, USB3 disks, etc. When at the desk and connected to the dock I actually use my MBP in clamshell mode so the keyboard I use is not the internal, but a USB KB I hooked up through the dock.
A while back I noticed that if I reboot my MBP while its connected to the dock I could no longer enter my password. I actually had to open my MBP and use the internal KB. This had not always been the case. I went through all kinds of troubleshooting including the tech staff at Elgato who was kind, responsive, and tried to be really helpful, but ultimately couldn’t fix the issue.
In hindsight it sounds a bit obvious, but it took me forever to figure out what had happened. Turns out my external KB stopped working after I started using FileVault on my MBP’s internal SSD. The password I was entering after reboot was no longer to just log me into my account, it was now required to actually encrypt my file system in order for the OS to load. Initially I suspected that the Mac EFI does not offer support for USB KBs through TB2. So unless the OS has already loaded the kexts, no dice with the KB. But it turned out that’s wrong too. I can in fact use the USB KB attached through my TB2 dock to enter the FileVault password if I unplug the USB KB from the dock and plug it back in first. I later noticed it’s the same thing for other USB3 peripherals. Until they are either disconnected/reconnected or the OS has loaded, nothing moves across the bus.
Does this make any sense to anybody here? Anybody else using FileVault, a TB dock, and a USB KB? I’m also curious if this is somehow an Elgato thing or if it’s the way Apple has implemented TB. The Elgato people realized the issue was connected to FileVault, but they weren’t familiar with the problem. They were willing to swap the dock, but since I’m pretty sure the dock itself is A-OK I wasn’t willing to be without it for several days until a replacement arrives (they wouldn’t ship first). The unplug/replug thing is annoying, but I can live with it unless somebody knowledgable comes up with a better idea.