As simple as the title suggests.
I've been handed a Wii by a friend of mine who wanted me to install HBC and all, only to find that it got semi bricked without having any kind of homebrew whatsoever.
The system menu is in Japanese and I can't get to the settings menu as you've already guessed.

All tutorials I found speak of installing bannerbomb which isn't working (thus concluded it's on 4.3) and gave absolutely no reaction once accessed the SD card.
Installing letterbomb requires MAC address and I can't reach that in my state.

Please help me, templars!!!

 

Can you get to the data management screen to copy a savefile to the SD card?

 

If the wii is was ever setup to use a wifi network, and is set to default use that network, use the aircrack suite to sniff its mac address. Or just use smash stack jap.

 

The Wii is from my friend and it was never set to work with my router ---> cant get MAC address from there.

I found a way to extract the MAC address from any save file created on a console and it worked in my case.
It appears the Wii was originally 4.2 Japanese and was updated to 4.3 US.
It was a missy situation but I managed thanks to the scene.

BTW the MAC extracting app is called "FE100-1.2b".
With this, you can install HomeBrew Channel on a semi bricked Wii and continue with changing region to your liking.
I changed it to US 4.1 then updated to latest via Wi(damn)Fi and letterbombed with goodies : )

 

I don't exactly know where my friend got this from, but I believe he bought it secondhand to the original user.
He's not much of a Wii gamer (until I converted him in a match of SSBB!) so he didn't give it much thought.