Since you have a Wii U formatted USB plugged in, you MUST install it to USB, or remove the USB when starting it. This has been discussed a few times in this thread previously.To NAND. Yes a WFSU formatted USB stick is plugged in. Would removing it while installing the channel fix it?
As a long time Loadiine (or WUP to sysNAND) user I'm kinda new to USB. Would it do me any harm to pull off the drive before boot and stick it in again before my next boot?
Is the Wii U just checking whether a drive is connected on boot and lists the games? Don't wanna mess around.