Reverting back to HDD to boot ESXi

I am new to vmware and am currently using vSphere 5 (Free).

After reading up on the ability of booting our HP DL380 booting off a USB stick, I decided to try it, and was successful. However, I am uncertain if this is really "best practice," as I have read there is some pros and cons to this method.

I have read posts that describe how to replicate my stick in case it goes dead, but my question is, can I revert back to placing ESXi back on the HDD, and how would I go about it?

Thanks in advance.