Okay, I'm pretty sure there is no hope, but I figured I'd post to see if maybe, just maybe, there is something I'll be able to do. I have an R4i (r4i.cn), and it wouldn't play the Adventure Time nds game, so I went to my website and downloaded the firmware updater and kernel and everything I need to update my r4. But when I started the firmware updater it caught itself in an error loop, I let it sit for a while in hopes that it would sort itself out but it would say there was an error and claim to be updating and rewriting Flash. Now when I stick it in my DS it doesn't show up. It displays that there is no game in the device. I didn't know if there was any hope as to something I could do, other than just buy a new r4?
You are on an NDS/NDSL or DSI/3DS? If on DSI/3DS, you didn't update your console right? Hopefully not. First back up the SD Micro content, then check if it's a mere issue of improper contact between SD and cart's metal elements. If it fail, have you tried re-formatting your SD Micro (make sure to back up content first!!!!), and then re-add the installation/updating files provided by R4iDS.cn. Make sure your battery is fully charged when updating, and make sure the SD Micro is properly in contact with the cart's elements. Follow installation/updating procedure as per mentioned in your cart's official website. If your computer doesn't even recoqnize the SD Micro, then likely it's dead. Get a new SD Card. If your SD Micro is ok, but your cart still isn't recoqnize then maybe the cart is dead.
I am using a DSi, but I haven't updated my system in quite some time because I use it for the r4. I tried your solutions, because why not, but they didn't work. It just displays "there is nothing inserted in the Game Card slot", and normally when my SD card is malfunctioning (because that has occurred a few times as well), it still shows the r4 in the slot, but the contents do not work. Alas I think I will end up buying a new r4.
If your SD Micro already been malfunctioning several times before the looping happened, and it's not even showing; best to buy a new card, that would include if the case is with the flash cartridge too. As Ethan said, when you did the updating prior to posting here, you said it went into a loop, it's most likely bricked.
