Read carefully the first post if you need root. For now it is the only way.please...i don't understand ..
You can also use Linux to format your sdcard to ext2. Or any other software for formatting sdcard to ext2 and moving update.zip to sdcard.
You don't need the post you quoted. It is for people who want to extract files from ROM.
If you have precise questions I'll try to answer them.
Sent from my new LG L90 D410 that is FINALLY ROOTED!!