RB206G management interface fails after factory reset

[jaclaz]

What do you EXACTLY mean by "saved" and "restored"?

I suspect you used a binary backup, that in some cases can produce strange issues when taken from one device and applied to a different one.
Check #17 and #18 here:

GP & CSA for Mikrotik devices

Preamble and disclaimer: The following is a numbered list of what is usually considered good practice or common sense advice when choosing, using, setting up or maintaining a Mikrotik router. It is my personal take on the matter, and in no way approved, endorsed or recommended, officially or unofficially, by Mikrotik or their partners or by anyone else. In other words you are perfectly free to ignore its contents, though they represent (IMHO) a sort of (useful) check list for people starting …