Your old solution used DarkCorp, which is generally discouraged as it modifies every single ios and can potentially interfere with other functions that expect stock ios's in these slots
Another alternative to play backup disks via the disk channel is to adjust your priiloader settings to use a custom ios for the system menu, like 249. However the handful of games that need a dif cios like 250, 248 or 251 will fail
Or... you can launch your usbloader and play backup disks from there (no need to rip to usb), and here u will be able to specify what IOS to use so you're not locked into just 1 like 249, and you can also apply other settings like video mode changes, cheats, etc
In case someone else is reading this in the future, all these solutions require the wii is either an older model that can play backup disks, or has a modchip allowing u to do the same