Was successful downgrading my niece's O3DS (non-XL) that was on firmware 2.X (was looking for a game cart to update firmware to hackable version).
Upgraded to 10.6 via system update. Used CN to boot HBL.
Initial downgrade crashed (not sure why, maybe I pressed 'upgrade' versus 'downgrade') which resulted in a partial downgraded system.
Updated CN to use 9.2 QR code.
Downgraded again and rebooted fine.
Need to double check tonight with the downgrade checker to confirm, but looks good.
Upgraded to 10.6 via system update. Used CN to boot HBL.
Initial downgrade crashed (not sure why, maybe I pressed 'upgrade' versus 'downgrade') which resulted in a partial downgraded system.
Updated CN to use 9.2 QR code.
Downgraded again and rebooted fine.
Need to double check tonight with the downgrade checker to confirm, but looks good.