Black screen after downgrading from SM 4.3U to SM4.1U-449
I have a black Wii with the System Menu 4.3U. I decided to softmod it using the "SoftMod Any Wii" guide. Everything went great until Chapter 2 Part 1 of the Guide where it recommends the downgrade to SM4.1U-449. The MD5 verified fine for all 3 wads of the SM4.1. The installation of all 3 wads through WiiMod completed ok. When I went back up to the list of all WiiMod functions I noticed that the "IOS" item had red font. I think it was white (as all other items) before starting the 4.1 wad install. After I pressed "home" on the Wii remote to exit WiiMod the TV screen went black and the Wii does not respond to the "reset" button. It makes a disc eject sound when I press the "eject" button (there is no disc of course). It also ignores any buttons on the remote. However if I long press the "power" button the Wii powers down. One more short press and the Wii powers up. However I still get the black screen.
I have the NAND backup files but I don't know how to use them. Please help me to restore my Wii. Many thanks in advance.