After rebooting my server (Lenovo System X), my ESXi instance starts to boot and then hangs up after the Yellow/Grey screen. I have a black screen, with a white "usb" on top.
I found similar issue with "scrath" or "ssh" text, but not "usb". I tried to reboot several times, with the same result.
I can't find any documentation about this behavior.
Note: my ESXi is installed on the hypervisor USB flash drive.