manual flashing in linux is probably the easiest way I think. Once you have installed the flasher all you do is go into terminal and cd into the directory of the firmware file you downloaded. Then use the tab shortcut to finish the command name(ex: type flas and hit tab and it will type flasher-3.5) then -F (start typing firmware name *tab* for auto-complete) then -f -R

so it look like

flasher-3.5 -F Firmwarefile -f -R

Remember everything is case sensitive.

linux will remember that command later in case you mess up your phone...just remember to cd to the directory