Hi, my son accidentally updated his 3ds xl to fw 4.5.0-10E, and it isn't recognising the acekard 2i. Is there any way to fix this, or...?
I find it odd that some of the answers to help with a DS flashcard is buy an overpriced 3DS one.
But indeed it looks like you will need a new DS flashcard or get a cheap DSLite. You do have a few 3DS compatible flash cards for DS games to pick from so check them over before picking while most would just say "Get a DSTwo!" which is a great card dont get me wrong but check in on the others and get the one to suit your needs, especially if you dont plan on trying to emulate GBA and such and just want to boot DS games the DSTwo might not quite be right for you and would cost you more for features you wouldn't use.
There is also some "R4" cards you can also look at that are more traditional with a lot less extra's but get the job done (I myself use a R4 Dual Core 3DS which was $8.99 since I have a GCW Zero for emulation so I only needed it for NDS roms)
The reason that the Gateway suggestion appeared so often is because the OP's 3DS was upgraded to a compatible FW. Almost every other post like this involves someone upgrading to >4.5. Thus, it's a rare opportunity where the OP could get full utility out of the purchase price, unlike the bulk of us who already had a DS flashcart when we got our Gateways.
Btw, if you think that Gateways are expensive, you should have seen the price of DS flashcarts when the scene first started with slot-2 loading. I paid $70 back in 2005 for my M3. The reason that Gateways are so expensive is because the 3DS scene is still so young and economy of scale hasn't kicked in yet. It wasn't until at least a few years into the DS flashcart scene before the prices dropped significantly when different R4 versions were popping up like herpes every other month.