I keep getting "An error has occurred. Hold down the POWER Button to...." each time the updater finishes downgrading and reboots, have to get into recovery to return it to 10.3
I'm using an O3DS U trying to install 9.2.0-20U-O3DS, I've tried downgrading with ironhax and menuhax with the same...
I got the "An error has occurred..." after getting a success in sysUpdate and rebooting and nothing else.
If that's your case, you have to get into Recovery Mode (L+R+A+D pad UP while power on) and download the update when when prompted.
If the update dies middle way, try again but turn off...
although i ended up accidentally changing my nand with no way of going back bc i didn't know you needed a gamecube controller to restore it (i have a wii minus/1.1, which doesn't have gamecube controller support)
and if i find the sd card i have my NAND backed up on, i can not only restore the NAND if i solder the right part in, but i can also put my NAND on dolphin, then i can play dolphin online, like PMEX Remix or MKWii Riibalanced