Bhyve Exited to UEFI Shell

I have a FreeNAS host where I run a few Bhyve virtual machine (VM) instances. Upon upgrading FreeNAS, I found some VMs did not boot successfully. It turns out that the VMs exited to UEFI Shell, and complained that it could not locate some efi file. The solution that works for me is discussed in this post.

To summarize, I followed the two steps procedure as described in the post:

1. Boot the VM into the guest operating system, in my case, CentOS 7, by (1) exiting the UEFI shell, (2) entering UEFI "Boot Maintenance Manager"; (3) choosing "Boot From File", and (4) browsing the directory and locating grubx64.efi under the folder named after the operating system, in my case, centos/grubx64.efi
2. Copy the efi file to BOOT/BOOTX64.EFI

Firewall Blocked Github: Connection refused

When I am at work, I encountered the following error while attempting to access Github,

ssh: connect to host github.com port 22: Connection refused

This could be the result that the corporate firewall blocked the SSH service (TCP port 22). In this case, we can inform the ssh client to use port 443 instead according to this Stack Overflow post. To do this, we add the following configuration for the ssh client,

cat >> ~/.ssh/config << END

Host github.com
  Hostname ssh.github.com
  Port 443

END

For me to use ssh to connect to Github, the Github official documentation turns out to be very helpful.