If you’re using an UEFI PC, you may encounter issues booting freeBSD and freeBSD-based operating systems. For example, the ‘Can’t find ‘/boot/entropy/’ error. If you are encountering this error, it may be due to your UEFI boot settings. freeBSD UEFI boot issues are a common occurrence and are almost always (if not always) remedied with a simple change to your BIOS settings.
I encountered this issue with freeBSD 12.0 on my HP Prodesk 400 G5 and I resolved it by choosing the BIOS setting: ‘Legacy Boot Enable, Secure Boot Disable’. On other PCs, just disable ‘secure boot’ and ‘enable legacy boot’. Secure boot may block freeBSD from booting because it may not recognize freeBSD’s bootloader signature.