My recollection is that reflashing does *not* clear the security code.
There are instructions around here on how to recover your security
code; you have to by hook or crook become root and then look in
one of the /dev/mtd* files and spot the string.

Andy

yes, the problem is phone will not boot up completely without a code, so I will not become a root on that device to have the code.
on Nokia N9 I've did a guide here how to backup your phone (asking for cone when booting), erase + reflash and restore backup with mo security code prompt. is here some common solution?

Oh, I see. The last time I lost my code was before I had it auto-lock, so I hadn't thought of that issue. Hopefully reflashing will clear enough config so the reflashed system is allowed to boot.

Have you looked at the 0xFFFF utility (crazy name, I know)? Among many functions, it can dump the /dev/mtd flash memory parts without the N810 having to be booted or anything (it's sort of a more flexible version of Nokia's "flasher" utility), and its
"-x" flag is probably exactly what you want (the entry lock_code is the config name for that code). Linux only, I think, so I don't know if that'll help you.

Andy