update.zip can only be update-binary'ed not flashed
The problem with fastboot boot recmod or fastboot flash boot recmod is that in neither case does it get the right command line.
Have you had EDL working before?
Only proceed if you can dig yourself out of a hole.
Code:
C:\>fastboot flash recovery recmod
C:\>fastboot flash misc misc-rec
C:\>fastboot reboot
(You can rename it without .prc)