Originally Posted by alresave
if your recovery is a zip file, unzip it and it will contain a img file (maybe recovery.img). You can flash that using
fastboot flash recovery recovery.img
Remember the img must be in the directory with the fastboot.exe and that the correct drivers are installed for it to work. Also it may not be called recovery.img so use the name of the file depending on what it was, then you can use fastboot reboot to reboot afterwards.
Fastboot boot recovery.img is a temp recovery flash I think?