do you know how this baking procedure works for graphic cards/notebooks with integrated graphic card? If not, please stop for a while and google for it. It's *very* risky, but, for graphic cards/notebook motherboards, it works for 90% of situations. Still, those rest 10% are, when you totally destroy Your device

Basically, first of all, you need to disassemble it as deep as it's possible. every part that can be removed, should be - to avoid cooking it. don't even think of putting it into oven with screen! Then, You pre-heat Your oven to ~200 C, and put motherboard there, for no longer that 8-10 minutes. You may hear some "cracking" sound due to PCB reacting @ high temperature - it's normal. Plastic parts (connectors, etc) may become yellow'ish. After set time, quickly remove it from the oven, and let it heat-off steady, preferably, overnight. After that, assemble everything and check if it works at all, by any chance, or even You got Your issue fixed.

As for my knowledge, You would be the first one ever to try "cooking repair" of Your N900 this way, so i'm somehow excited about outcome. Still, consider it carefully, before proceeding. You may still use Your N900 with SD card (home and MyDocs set here, by altering bootup scripts), for example 32GB one. Also, You may sell it as damaged.

Or You may go berserker and try cooking method - insane, but witch chances to fix it completely (or break to completely). Choice is Yours...

/Estel

Ps.

Despite I tried to describe "cooking" process with details, It's possible that I've missed something (cooking time - I recall it being 8-10 minutes, but I'm pretty sure it's not strict - every device may react differently. N900 motherboard is much smaller than Notebook's motherboards, so I would settle with 8 minutes, not 10), my knowledge there is purely theoretical, based on countless experiences of other people. so, if You decide to process with it, be sure to google around, just in case.