Retired WiiHacks Staff
I recommend 3.1-4.1 SoftMod for any wii and if you have a wii bought before September 2008 then you should be able to install bootmii as boot2.
The cIOS installation allows it to be possible to play your game backups. But for the installation to work it needs a vulnerable IOS that it could run of off. This should be pretty safe since it doesn't touch the system IOS which in your case is IOS60.
i used 3.1-4.1 on my 4.1u wii and it worked and i now use usbloadergx to load games off a passport