PS3 Slim dual boot (help)

Hi, I bought a E3 flasher a couple of days ago to downgrade and dual boot.
I have a slim and its is "downgrade able"... I asked if i needed to solder on this forum and someguys said no, but today I read that someone asked the same thing and he needed to solder :S Please help me... I bought it because I thought it didnt need solder :/