When I need to move large files or a lot of smaller files (like when backing up the uSD or when I've installed A9LH) I simply remove the back cover and used my "clear plastic shield" in it's place, since the hinges connecting the parts of the shield are broken it's easy to put and remove. And those shields are actually cheap.It's annoying, but there are workarounds (none of them really pretty though):
- Cut a hole in the removable battery cover/bottom lid where the uSD slot is so you can get to it whether it's on or off
- Dremel out the screws on the battery cover so they're not there anymore, making it easier to take it off (I know you can leave it on unscrewed, but sometimes they get kind of stuck)
- Get one of those weird uSD extension cables from AliExpress or whatever site had them, and have an easier to access uSD slot that sticks out of your console
I suppose one could also try removing the game card slot and relocating the uSD slot to there. No clue if your N3DS would still boot after that though. That, or relocate the uSD slot near the charging jack or somewhere else.
on topic: What I like the best on N3DS over the O3DS.
1st - More power to homebrews
2nd - forcing New clock mode + L2 memory to CTR Games (only downside is that some of them may have random freezing or locking, like Senran Kagura 2 that got stuck on loading screens sometimes).
3rd - Included second analog input + ZR/ZL, included NFC reader/writer.