Very interesting! Though not working as intended, trying to do so clearly changed the timing of the freeze. So it might not be about the card reader per se, but its contacts. Maybe wiping them with alcohol and reconnecting the reader back to the motherboard could help. I'll try that while I'm waiting for the replacement. Thanks again!Just a tip, when mine was acting up (sd card reader) i accidentally discovered that the 3ds starts working after i put some pressure on the back cover, the area when you insert the sdcard, and it immediately freezes or gives an Arm11 whenever i let go. So if you want to try it, put a piece of paper close to that area, thick enough to apply sufficient pressure on the sd reader and screw it tightly. It might not work for you, but it's worth a try imo, specially if you don't have an sd reader replacement yet..