I just did this to keep my xbox going until gta 5 came out on PC no point in getting it fixed right lol.
Dude, lead free solder doesn't melt until 220 *C... How are you supposed to reflow at 120... Heat from soldering does nothing to chip life, as long as you are within the manufacturers soldering heat limits. The Chip wears out from internal electrically generated heat, which is completely different. How do you think they solder GPUs to graphics cards that have a thermal limit of about 100*C.... Also 400 *C wtf... Have you ever soldered in your life? 60-40 solder melts at 188 *C
FYI I've done this 5 times to my xbox since 2008. it still works everytime after. I don't even use it anymore so theres no point in getting it reflowed with lead solder.