Ok, make a backup copy of that nand.bin.
Open your nand.bin in ohneschwanzenegger
Format the nand.bin with ohneschwanzenegger
Install 4.3u with ohneschwanzenegger
Set you serial number to match the console when creating your settings.txt
Check your new nand.bin with nand.bin check, all should look good
Restore the new nand.bin with bootmii
After the nand restore, all should be well
Softmod the wii again.