l_oliveira can you try to create an autoboot disk that it starts HBC and from there run one of Waninkokos downgrade tools....May this repair the bricked wii. Of course do that if this Wii mobo you bought is already bricked.
Sorry for not trying this but i have one and only Wii.
The only prob is that Waninkokos downgrade tools, i think, they need wireless connection to download some files. But wii in this service mode....i don't know maybe it doesn't initialize the wireless.
After that a clever guy out there will create a tool to back up our working WiiOS files and generate a autoboot disk that writes those files back to flash. Of course i just say things and things that i don't even know how hard is to make them.