Your cart is almost similar to r4igold.cc and r4isdhc.hk. I had bricked 2 of my r4isdhc.hk carts before. 1st was when i used retrogamefan's kernel and 2nd was when I was writing to the SPI flash when it somehow trashed something in the flash chip. I got help from irc when someone gave me a dump of their r4isdhc.hk dual core cart, but for some reason, the original kernel wouldn't work anymore and will just give me a white screen. After buying at least 2 more of these carts, I then learned that these carts (at least the one with SpongeBob icon) has some unique key stored in flash, that if you used and write it to a different flash chip, it won't boot to the kernel. And this key is unique per flash chip (not per cart). So I searched and found an old kernel (which I believe don't check for this key) from R4iGold.cc (the one I gave you) which at least worked and let me play NDS games again.