BootMii Reports being "too dangerous" for restore.

I have an old Wii that had dust in it for reading doble-layer discs, so I got a new Wii and I plan to return the old one. I backed up all of the Wii's old data with bootmii, and when I attempt to put it on the new one (bootmii and homebrew channel are already installed), it says:

RestoreMii, NAND ID: ecdc1095
Checking boot2...
BootMii not found, too dangerous to continue! If your SD is corrupt of restore is interrupted, you will be unable to boot to fix it. If you are SURE you want to do this, press A+B+X+Y
Otherwise press any key to exit.

The NAND ID is the same ID as the old Wii, but I'm not sure if that matters. I do not have a GameCube controller so I can not press all of the buttons. How do I fix this? Both Wiis have BootMii installed as an IOS. The old wii is very old, I got it in 2007, and the new one was bought yesterday.

This always happens with BootMii/IOS, it's just to ensure that you don't try to restore a NAND backup, have the power go out, and have a bricked Wii. If you have safe power conditions, you could do it. However, you will have to use Betwiin and make sure both Wiis have the same boot2 and boot1 versions. If you can't use Betwiin or either is false, you can't do it.

I encountered this message as well when trying to restore my NAND file to the same Wii. I'm unable to install BootMii as Boot2, and when I try to press A+B+X+Y it returns to the previous menu.

Well, BootMii/boot2 is the only one that can restore a NAND backup period. If BootMii/IOS attempted to restore it, it would overwrite itself in the process, which is very dangerous or it could do worse and leave it in a brick/crap state.
If you can't install as BootMii/boot2, then that means that you have a newer Wii with boot2v4, making it impossible to install.

If you need to use brick recovery for new Wii systems, Priiloader gets the job done too, it will install before the System Menu's boot, making it possible to boot in to BootMii/IOS, so you could get in there if you needed too. You could also use it to get into the homebrew channel, so you could easily reverse bricks caused by Homebrew software.
The only down side to Priiloader is you can not restore bricks that have corrupted boot2, or NAND.

Bootmii/IOS can restore a NAND backup, and it probably will work fine. It is just as likely to be sucessfull as restoring a NAND backup with Bootmii/boot2 (which almost always works). The difference is that if the restore does fail but Bootmii is installed as boot2, you can fix it. However, if the restore fails and Bootmii is only installed as IOS, the wii can't be fixed without a hardware NAND programmer. Restoring a NAND backup with Bootmii/IOS is rarely, if ever, a good idea, but it can be done and will probably work.

Boot1c (the fixed version) was installed in some wiis before boot2v4 was, so Bootmii can't be installed as boot2 on some wiis that were shipped with an older boot2 version. The boot2 version has nothing to do with whether Bootmii can be installed as boot2.

Priiloader only provides protection from banner bricks and such. Anything else would remove Priiloader. Also, its ability to launch Bootmii/IOS provides no additional brick protection, since restoring a NAND backup with Bootmii/IOS is more dangerous than deleting the WAD causing the brick, or removing a bad theme if that is the cause.