tried with all three variants?

I dont know can you do the soldering, but it's very attentive work and dangerous, because the flash memory chip located on main processcor chip, they are some cohesive, to unsolder then resolder with new one of memory chip you must have some experience in such works, other wise take N9 to Nokia Care if you have warranty or take it mobile-electronic service (or something like that), they will do it (or just buy new motherboard for N9,this is some expensive way but easyest).