well, i didn't told i want to flash the emmc... i asked if this is the only way i can have the SIM working back again.
and as i mentioned i cannot see the fiasco image in the download page.

to have it understood.
what to your opinion the steps i need to do to have my SIM card working again.
you mentioned i did a mistake and downgraded...how can i upgrade?
with which file? with which kind of file?
how many flash operations i need to go from my current status to working and functioning N900 with SIM working.
please be specific as much as you can.
thank you again for all you help and valuable posts.