other vector i tried to use without success:
Setting>menu (top border) > Restore original settings that didn't work and SIM card still not recognized.

right now i live in the middle east so i need to use the sepcific middle east firmware when needed.
so what you wrote - i can use all the way the NSU and it will help me to upgrade etc instead of flashing and flashing with

the various images?

and if i cannot use only the NSU i need to flash with the following order?
1) latest GLOBAL fiasco image (on the page its Latest Maemo 5 Global release for Nokia N900)
RX-51_2009SE_10.2010.19-1_PR_COMBINED_MR0_ARM.bin
2) Vanilla version of the eMMC content for Nokia N900
RX-51_2009SE_1.2009.41-1.VANILLA_PR_EMMC_MR0_ARM.bin
3) global (or middle east/personalized) - Maemo 5 Global release for Nokia N900
RX-51_2009SE_1.2009.42-11_PR_COMBINED_MR0_ARM.bin

and all the flahes will be done like the flash that worked me before.