where should firmware be when installing on a mr3040 router? multiple instructions varry on this i noiced, and does it even matter?

I have read over a few different guides for installing the PirateBox on the mr3040 ( the battery powered TP-Link router )
I noticed the place where you have the firmware is not addressed on the main guide on piratebox.cc so is it simply left on the computer then seleted for use with the firmware upgrade? OR should you do as many guides say and put the firmware with the install file and put them both on the flash drive then put the drive in, boot it, and use the upgrade firmware tool that way?

AND does it even matter wich way you do it?

Thanks for any feedback,
-SnapCount