QUOTE(liamlain @ May 27 2010, 12:12 PM)
still scare to touch ths step,scare will brick my device.
i hv question about update firmware via OTA and NSU.
yesterday i update firmware at app manager,after update complete my application still ther,
so i thnk is it update via OTA the application will still maintain,and NSU will delete all the application(like format)
so if i dnt use flasher software to format my device,can reinstall firmware via NSU?(coz this is much more easy for me)

dont be scare, brick ur device is nothing. u can always reflash it back to restore the functionality in case something goes wrong. trust me, i've been the worst. yesterday is seems the bad day for me, but in the end, i learn something new.
updating via OTA and NSU is basically the same, u still need to update via NSU in the end. IMHO, flashing using flasher is really quick, less-hassle if u know what are u doing. but as there are many guides on how to flash by using flasher, including the one aspire2006 put it at FP, even inexperienced user can do it
btw, if u still scare u might brick ur n900, updating via NSU is 'safest'.