What do I have?

So I bought a flashcart a long time ago and it's not apparently what it says it is.The sticker on the front of it is black with silver highlights (a dot design and the wording). The words read on one line, "R4i" (the "i" is in a small circle to the upper right of the R4), underneath R4 is "Upgrade", underneath that is "Revolution for DS", then under that, "(NDSi/NDSL/NDS)", and under that, "WWW.R4I-SDHC.COM"R4i
Upgrade
Revolution for DS
(NDSi/NDSL/NDS)
WWW.R4I-SDHC.COMI ask because I can't seem to find an update for my firmware on the mentioned website an I keep hear about these custom firmwares that are much better. I want to know if I can use one and which ones I can use.Thanks in advance.

http://www.r4i-sdhc.com/indexe.asp
thats the website, i just tried it and its working. and you wont be able to run the other firmwares, you can try though. here is the link:
http://forum.romulation.net/index.php?topic=43121.0